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Патент USA US3051803

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Aug- 28, 1962
M. A. CLEMENT
3,051,789
TELEPHONE SYSTEM mcwnm; MAGNETIC STORAGE DEVICE
Filed Sept. 11, 1959
6 Sheets-Sheet 1
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INVENTOR.
MILTON A. CLEMENT
BY
ATTORNEY
Aug. 28, 1962
3,051,789
M. A. CLEMENT
TELEPHONE SYSTEM INCLUDING MAGNETIC STORAGE DEVICE
Filed Sept. 11, 1959
6 Sheets-Sheet 6
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United States Patent
6
ice
3,051,739
Patented Aug. 28,‘
1
prevent the conditioning of any further recorders when
3,051,789
TELEPHONE SYSTEM lNCLUDmG MAGNETEC
STORAGE DEVICE
Milton A. Clement, Rochester, N.Y., assignor to General
Dynamics Corporation, Rochester, N.Y., a corporation
of Delaware
Filed Sept. 11, 1959, Ser. No. 839,396
6 Claims. (Cl. 179—7.1)
This invention relates to an automatic toll ticketing
system and, more particularly, to a system of this type
the recorder next following a seized recorder is engaged
in storing toll call data.
A further object is to provide an automatic toll ticket
ing system including new and improved means for con
trolling the movement of the magnetic tape in each of
a plurality of successively seized trunk recorders.
Other objects and advantages of the present invention
will become apparent from the ensuing description of an’
illustrative embodiment thereof in the course of which
reference is had to the acompanying drawings in which:
FIG. 1 is a block diagram illustrating conventional
including new and improved magnetic recorder control
automatic telephone switching equipment in a local o?ice
means.
from which toll calls to be ticketed are extended;
In the automatic toll ticketing system shown and de
FIGS. 2. to 5, inclusive, form a schematic drawing
scribed in the copending application of M. A. Clement 15
illustrating the details of a trunk circuit embodying the
and B. A. Harris, Serial No. 536,579, ?led September
present invention;
276, 1955, which application is assigned to the same as
FIG. 6 is a schematic diagram partially in block form
signee as the present application, items of information
illustrating a party matrix switching circuit in conjunc
pertaining to toll calls successively placed over a trunk
circuit are automatically recorded in a trunk recorder 20 tion with other calling subscriber identifying equipment;
and
individual to the trunk circuit. These recording opera
FIG. 7 is a block diagram disclosing the manner in’
tions are controlled by certain components in the trunk
which FIGS. 2 to 6, inclusive, are positioned adjacent‘
circuit and are performed at different time intervals dur
each other to form a complete circuit diagram of a sys
ing the extension of the connection. The trunk recorder,
which can be of the type shown in Gleason Patent No. 25 tem embodying the present invention.
2,867,435, includes an endless loop of magnetic tape
on which control and data representing signals are re
In general, the trunk circuit of the present invention
is adapted to be utilized in an automatic toll ticketing
system of the type disclosed in the above identi?ed co
corded. The endless loop of tape has a home position
pending Clement et al. application. As shown therein,
or effective beginning from which the tape is moved
step-by-step as information is magnetically recorded 30 the items of information pertaining to a toll call are
collected in a trunk recorder or storage device individual
thereon. This effective beginning or home position is
to an outgoing toll trunk under the control of pulses
de?ned by indicia carried on the tape, such as conductive
dialed at a calling substation, the trunk recorders being
foil segments or perforations.
capable of storing the items of information pertaining
In a system of the type shown in the above identi?ed
to a plurality of toll calls. At a selected time of day,
copending application, the trunk recorders associated with
such as the. early hours of the morning in which the
the trunks in a particular group are played back in se
traffic level on the system is relatively low, the trunk
quence by a playback control circuit including switch
circuit is seized by recording and playback facilities to
ing means which sequentially seize each of the idle
permit the items of information pertaining to a plurality
trunks and their associated recorders. The magnetic
of calls to be sequentially played back from the trunk
tape in the seized recorder is returned to its home posi
recorder to control recording facilities for producing a
tion, and the stored information thereon is reproduced
group of permanent records each including the items
and transmitted to recorder facilities which provide a
of information pertaining to a single toll call.
permanent record of the toll call data. This prior sys
More speci?cally and referring to FIGS. 1 to 6, inclu
tem also includes an advance circuit means for auto
matically advancing the record medium or magnetic tape 45 sive, of the drawings, assuming that a toll call which‘ is
to Ibe automatically ticketed is to be extended from a call—
in the trunk recorder next succeeding or following the
ing substation A to a called substation B located in av
seized trunk circuit to its eifective beginning or home
remote area, the subscriber at the substation A goes olf
position to reduce the holding time of the trunk circuit
hook to extend a circuit to a line circuit 100 individual
when this next succeeding trunk circuit is played back,
each trunk circuit being busied out when seized or when 50 thereto, the line circuit 100 placing an allotter 101 in
operation so that a link comprising a ?nder 102 and a
the record medium has been advanced to its home posi
selector 104- is placed in ‘operation to search for and seize
tion prior to seizure. This prior circuit arrangement
the calling line circuit 100. In response to the comple
aessentially
given group,
provides
so that,
a series
if a next
circuit
succeeding
linking the
trunk
trunks
circuit
tion of the association ‘between the ?nder-selector link
is busy due to the performance of a data recording oper 55 including the units 102 and 104 with the line circuit 100,‘
ation when the preceding trunk circuit is seized for play
the calling subscribed is advised that dialing may be ini
back, the series circuit homes the magnetic tape in the
tiated to extend the connection to the called subscriber B.
next idle trunk recorder and thus places three of the
The ?rst digit dialed at the calling substation A is an
trunk circuits in the group in a busy condition. Under
access digit which must be dialed in order to extend the
certain operating conditions, the number of busy trunks
connection tothe group of trunks equipped with automatic
is such as to adversely affect the trailic handling capacity
toll ticketing means which are utilized to extend the con
of the system.
nection to the remote area. Assuming that the access digit
Accordingly, one object of the present invention is
is “8,” ‘in response to the ‘dialing of the access digit “8,”
to provide a new and improved trunk or adapter circuit.
rthe selector 104 advances its wipers to the eighth level
Another object is to provide new and improved ad 65 and thereafter automatically searches over the multiples
vance circuit means which prevents an excessive number
in the eighth level to seize an idle outgoing trunk extend
of trunk circuits from being placed in a busy condition.
ing to the desired remote area. Assuming that the'trunk
A further object is to provide an automatic toll ticket
circuit shown in FIGS. 2 to 5, inclusive, is the ?rst idle
ing system having a plurality of serially related magnetic
trunk circuit in the eighth level of the selector '104, the
recorders which are automatically and individually con 70 calling loop circuit is extended to this trunk circuit, there
ditioned for operation by the seizure of a preceding re
by to prepare the trunk circuit for controlling the exten~
corder in the sequence and which are interlocked to
sion of the connection rto the called substation B and for
3,051,789
-
4
3
corder 500. More speci?cally, the identi?er sender al
lotter, which may be of the type disclosed in the above
identi?ed copending Clement et al. application, allots
recording the items of information pertaining to the toll
call in a trunk recorder 500 which is individual to this
trunk circuit.
'
The ?rst item of information dialed at the calling sub
station A following the seizure of an idle trunk circuit is
a dialed party digit which has an arbitrary value if the
calling substation A is on a private line, which has a value
an idle one of a plurality of identi?er senders, similar to
an identi?er sender 310, to the calling trunk circuit. The
identi?er sender 310 may be of the type disclosed in the
above identi?ed copending Clement et al. application or
may be of the type disclosed in the copending applica
tion of Ben A. Harris, Serial No. 518,952, ?led April
line multiparty line, and which has a value corresponding 10 18, 1956, which application is assigned to the same as
representing the units digit of the directory number of the
calling substation if the substation A is on a terminal per
signee as the present application. In response to the com
pletion of the association of the identi?er sender 310
with the trunk circuit, a power supply circuit 210, which
is also of the type disclosed in the above identi?ed co
to the position of thecalling substation A on a multiparty
line'if the multiparty service on the line is provided on
a terminal per station basis. This dialed party digit is not
repeated to remote switching equipment 300 but rather
is simultaneously recorded in the trunk recorder or stor
age device 500 and utilized to control the setting of a
stepping switch in the
circuit. The ?nal setting of
the stepping switch operates a selected number of party
digit register relays to prepare a single marking path on
pending Clement et al. application, is rendered e?ective
to supply an identi?cation potential over the HS lead of
the extended switch train to selectively energize an iden
ti?c-ation conductor 110 which is individual to the calling
line circuit 100 and which terminates in- a terminal 111.
one of '?ve conductors representing parties 1 or 6, 2 or 7, 20 The terminal 111 is selectively connected to an identi
?cation matrix circuit 680, which is also of the type dis
3 or 8, 4 or 9, and 5 or lO'and to prepare a single marking
closed in the above identi?ed copending Clement et al.
path on a pair of conductors representing parties one to
application, in accordance with the type of service pro
?ve or parties six'to ten. These conductors extend to a
vided to the calling substation A. In the event that the
party matrix switching circuit 600 and control this circuit
ata later point in’ the data recording process to select .a 25 substation A is on a private line, the terminal 111 is se
lectively interconnected with a private line and terminal
proper control vcomponent or party matrix for automati
per-line matrix 640 in accordance with the digits forming
the directory number of the calling substation A. Also,
cally determining the ‘directory number of a, calling sub
station on a terminal per station multiparty line.
Fol
if the calling substation A is located on a terminal per
tlowing the completion of the dialing of the dialed party
digit by the calling subscriber at the substation A, the 30 line multiparty line, the terminal 111 is connected'to the
matrix 640 so as to provide marking conditions represent
stepping switch in the trunk circuit is returned to a normal
ing the thousands, hundreds, and tens digits of the direc
condition and the’ trunk circuit is rendered capable of
transmitting subsequently dialed digits to control the oper
tory number of the substation A, the units digit 'being pro
vided 'by the dialed party digit as described above. If
ation of the remote switching equipment 300 to extend the
35 the calling substation A is located on a terminal per sta
connection to the called subscriber B.
tion multiparty line, the terminal 111 is connected in
V The next item of information dialed by the subscriber
multiple to all of a plurality of ten party matrices of
at the stationrA is the group of digits forming the direc
which only a party one matrix 610, a party two matrix
tory number of the called substation B, and, assuming
620, and a party three matrix 630 are shownin the draw,
that a conventional “2-5” numbering scheme is utilized,
the subscriber at the station A dials seven digits, all of 40 ings so. that as many as ten separate marking conditions
which are simultaneously recorded in the trunk recorder
are established in the identi?cation matrix circuit 680 in
accordance with the different [groups of digits forming the
500 and repeated over the outgoing ‘trunk to the remote
switching equipment 300, thereby to extend the connec
directory numbers of all of the substations on the terminal
tion to the called substation B. Simultaneously with thus
per station multiparty line on which the station A is
utilizing the dialed digits representing the directory num 45
ber of the called substation B, the trunk circuit advances
the stepping switch therein in the interdigit interval so as
to count the dialed switch operating digits so as to render
the trunk circuit incapable of repeating additional digits
over the outgoing trunk after a predetermined number of
digits, i.e. seven, have been dialed.
In response to the receipt of answering supervisory sig
nals from the remote switching equipment 300, a motor
driven timing mechanism which is adapted to provide a
located;
‘
In the event'that ‘the terminal 111 is connected to the
private line and terminal per line matrix 640, the energi
zation thereof selectively operates an identi?er circuit
690, which may be of the type disclosed in either of the
50 above identi?ed copending Clement et ‘al. or Harris appli
cations, to provide marking conditions extending to the
identi?er sender 310 associated with the trunk circuit rep
resenting the digits forming the directory number of the
calling substation on either the private line or the terminal
control impulse at a selected time interval, such as one 55 per line multiparty line. Alternatively, if the calling sub
to two seconds, following the receipt of answering super
station A is located on a terminal per station multiparty
vision and other pulses at one minute intervals represent
line, ‘marking conditions representing di?erent designa
ing elapsed time for the call is rendered effective so that,
' tions are established in any number of the individual party
if the connection is not released within the ?rst short
matrices 610, 620', and 630. To determine the proper
time interval of from one to two seconds, the trunk cir 60 one of these matrices to be interconnected with the input
cuit is advised that the call is to be ticketed and initiates
to the identi?er circuit 690, the party matrix switching
the recording ‘of date and time information in the trunk
circuit 600 is utilized. As described above, one ‘or more
recorder 500. VMore speci?cally, the general system in
cludes a clock-calendar circuit 220 of the type disclosed
of the group of the party register relays is selectively
operated under the control of the stepping switch in the
in the albove identi?ed Clement et al. application which, 65 trunk'circuit in response to the dialing of the dialed party
digit. In response to the receipt of information indicating
upon actuation, provides a series of pulses representing
the date and time on which the call being ticketed was
that the identi?er sender 310 has been associated with the
placed, these pulses ‘being recorded in the trunk recorder
trunk circuit, ground is applied to the paths prepared by
the selective operation of the party register relays to se
500.
In response to the completion of the storage of the 70 lectively operate the party matrix switching circuit 600 so
that only a single one of the ten party matrices including
clock-calendar information. in the
recorder 500,
the trunk circuit applies ground to an identi?er sender
the matrices 610, 620, and 630 is cut through to the input
of the identi?er circuit, thereby to provide signals to the
allotter (not shown) to initiate the automatic determi
nation of the directory number of the calling substation
identi?er sender 310 representing only a single one of the
7A and the storage of this information in the trunk re 75 directory numbers in accordance with the position of the
3,051,789
5
calling substation A on the terminal per station multi
party line.
In response to receiving calling subscriber designation
digits from the identi?er circuit 690, the identi?er sender
6
duction of records, each of which relates to one of the
complete calls whose data is recorded in the seized trunk
recorder.
Incident to seizing the ?rst trunk circuit, an advance
circuit is completed extending to control means in the
next trunk circuit to which the playback switching means
has access, which control means, when operated, initiates
the movement of the magnetic tape in the next succeed
ing trunk recorder to its effective beginning so that, when
releases ‘the identi?er sender allotter, the identi?er circuit
690, the identi?cation matrix circuit 680, and the party
matrix switching circuit 600, and removes the identi?ca
tion potential from the HS lead of the extended switch
train and the identi?cation conductor 11%, thereby to re
lease the common equipment components for use in iden 10 this next succeeding trunk circuit is seized, the delay in
herent in advancing the magnetic tape to its effective be
tifying a subscriber involved in a subsequently placed toll
ginning is obviated. The return of the magnetic tape to
call. If satisfactory calling subscriber data is provided,
its home condition, however, places the trunk circuit in
the identi?er sender 31f) initiates the transmission of a‘
a busy condition, thus preventing its seizure for recording
series of pulses to the trunk recorder 50!) in accordance
items of information pertaining to toll calls. In the prior
with the digital information stored in the sender 310
trunk circuit disclosed in the above identi?ed copending
representing the designation of the calling substation A.
Clement et a1. application, the control means for ad
However, if a satisfactory calling subscriber identi?cation
vancing the magnetic tape to its effective beginning in
is not provided, the identi?er sender 31E) prevents the con
advance of the seizure of the trunk circuit with which
tinuation of the connection and arrests ‘the recording of
each of the trurk recorders is associated was such that,
additional toll call data.
under certain operating conditions such as a busy condi
Following the completion of the transmission of the
iIlOIl of a given one or more of the trunk circuits, the ad
necessary information representing the directory number
vance circuit for returning the magnetic tape to its effec
of the calling substation A, the identi?er sender 310 is re
tive beginning was effectively extended to the ?rst idle
stored to its normal condition, and the timing device indi
trunk circuit. In this manner, it was possible for virtual
vidual to the trunk circuit transmits duration impulses
ly all of the trunk circuits in a given trunk group to be
at one minute intervals which are stored in the storage
placed in la busycondition either due to the recording
device or trunk recorder 59%}, thereby to provide a record
of the items of information or due to the return of the
of the length of the toll call. When the connection is re
magnetic tapes to their effective beginning. Thus, with
leased, the storage of the duration impulses in the trunk
all of the trunk circuits in a busy condition for one rea
recorder 59% is terminated, and the stepping switch, which
son or another, the traf?c handling capabilities of the
‘has remained in a position representing the number of
trunk group was materially reduced. Accordingly, in
dialed switch extending digits, is restored to a normal
the trunk circuit of the present invention, the control
position. This stepping switch thereafter cooperates with
means or advance circuit means for advancing the mag
a pulse generating source in the trunk circuit to sequen
netic tapes in succeeding trunk circuits to their effective
tially advance an elongated medium forming the record
home positions is so arranged that, if ‘any given trunk
medium in the trunk recorder 530 through a series of
circuit is engaged in recording items of information
steps which are counted by the stepping switch to provide
pertaining
to a toll call during the time in which a play
a measured run-0E for spacing the previously recorded
items pertaining to ‘the toll call just completed from the
back operation is being performed, the advance circuit
items of information pertaining to the next toll call placed 40 for the next succeeding trunk circuit is interrupted to pre
vent placing an excessive number of trunk circuits in a
through the trunk circuit. Prior to spacing out the elon
busy condition. However, this series circuit arrangement
gated mediurn, the trunk recorder records an end-'of-call
\is such that if the trunk circuit has been placed in a busy
code on the elongated record medium representing the end
condition due to the manual operation of busying means
of the item of information pertaining to the toll call.
Following the completion of the spacing operation under 45 or due to the establishment of an alarm condition in
the trunk circuit, the series circuit relationship is main
the control of the stepping switch, the stepping switch
tained intact so that a trunk circuit which is busy for one
is restored to its normal condition together with the re
mainder of the components in the trunk circuit, thereby
to permit the trunk circuit to be utilized in controlling
items of information pertaining to a plurality of subse
quently extended toll calls.
To initiate a routine playback operation in which the
items of information stored in a plurality of trunk re
corders similar to the trunk recorder 5% are transmitted
to recording facilities 41%, which may be of the type
disclosed in the ‘above identi?ed copending Clement et al.
application, a start ground is forwarded to the recording
of these reasons is effectively bypassed and the next suc
ceeding idle trunk circuit is operated to return- the mag
netic tape in the trunk recorder individual thereto to its
effective beginning.
Following the completion of the transmission of all
of the items stored in any given one of the trunk recorders,
the trunk circuit associated therewith ?rst returns the
magnetic tape to its effective beginning and thereafter
renders the stepping switch and the pulse generating
means therein effective to provide a measured run-off
or a preselected vdistance between the effective beginning
means 416 at a selected time of day, preferably during
and the position on the elongated record medium at which
the early morning hours, so that the recording means 419
the items of information pertaining to the ?rst toll call are
is placed in operation to seize a playback control circuit 60 to be recorded. In response to the completion of the run
4%, which also may be of the general type disclosed in the
off operation, the trunk circuit is restored to a normal
above identi?ed copending Clement et al. application. In
condition in which it is capable of being seized by line
response to seizure, the playback control circuit 400 places
extending means and utilized in controlling the recording
a switching means therein in operation to search for and
of items of information pertaining to toll calls. Follow
sequentially seize the plurality of trunk circuits to which 65 ing the completion of the playback of all of the trunk
it has access. In seizing the ?rst trunk circuit, this trunk
recorders associated with trunk circuits to which the play—
circuit is operated to advance the magnetic tape in the
back control circuit has access, the playback control cir
recorder individual thereto to its effective beginning and
cuit 400 and the recording facilities 410 are restored to a
thereafter movement of the magnetic tape under the con
normal condition.
.
trol of the trunk circuit is terminated and transferred to 70
‘It is often desirable, in providing proper maintenance
the playback control circuit 4%. The playback control
for the toll ticketing facilities and including the trunk
circuit 4%, working in conjunction with the recording
circuit, to dial the items of information pertaining to a
facilities 410, intermittently advances the magnetic tape
so that the items of information stored therein are trans
test call directly into the trunk circuit, thereby to provide
the trunk recorder 50% with the items of information per
mitted to the recording facilities 410 to control the pro 75 taining to ‘a test call, or to monitor the items of informa
3,051,785?
contacts are located followed by the alphabetical char
tion being recorded in the trunk recorder 500 pertaining
to a normal toll call; To permit the monitoring of items
of information pertaining to a regularly established toll
call, the trunk circuit is provided with test means per
mitting the connection of a monitoring or test device
across the tip and ring conductors of the connection ex
tended to the trunk circuit, thereby to audibly or visibly’
acters identifying the key and one or more numerical
characters individually designating the different contact
pairs of the key which appear in the same ?gure of the
drawings. For instance, an alarm key ALMK includes
the pair of contacts 4ALMK1 'located in FIG. 4 of the
drawings.
monitor the dialed information being supplied thereto.
Alternatively, if it is desired to manually and directly in
7
V
The remaining components in the schematic diagram
are identi?ed by solely numerical designations in which
sert information pertaining to a test call directly into the 10 the digits other than the last two designate the ?gure of
trunk circuit for recording by the trunk recorder 500, the
the drawings on which the element is located. For in
test means are utilized in conjunction with a manually.
stance, the identi?er sender 310 is located in FIG. 3 of
operated busy key, vthe conjoint operation of which per
the drawings, whereas the identi?er circuit 690 is located
mits a direct manually controlled recording of test cal-l
in FIG. 6 of'the drawings.
data in the trunk recorder 5'00.
.
-
-
'
In the prior trunk circuits of the type disclosed in the
above identi?ed copending Clement et al. application, it
is notpossible to directly dial test 'call information into
the trunk recorder 500 inasmuch as, as described above,
the trunk circuit is forcibly returned to a released con
dition in the event that the identi?er sender 310 is not
provided with a satisfactory ‘calling line identi?cation, and,
since the provision of this information is dependent upon
returning an identi?cation potential over an extended
switch train to the identi?cation matrix 689, the record
ing of test call data produced by dialing directly into the
15
'
’
TRUNK RECORDER 500
The trunk recorder 560 is of the type disclosed in the
' copending application of Howard S. Gleason, Serial No.
378,209, ?led September 3, 1953, which application is
assigned to the same assignee as the present application.
In general, the recorder 500‘ comprises a base plate on
which is detachably mounted a magazine containing an
endless loop of magnetic tape which is stored in random
layer fashion. A portion of the magnetic tape, which is
disposed outside of the magazine, is moved relative to a
pair of transducing heads by one of a pair of driving
trunk circuit would be interrupted at the recording of the
means. The transducing heads comprise a record-re
calling subscriber ‘designation because of the lack of an
produce space pulse head 549 and a record-reproduce
extended switch train to the trunk circuit. However, in
mark pulse head 520' having two magnetic gaps which are
the trunk circuit of the present invention, the test means 30 disposed adjacent contiguous transversely spaced por
includes means for supplying an identi?cation potential
tions of the magnetic tape to de?ne two separate chan
directly from the trunk circuit to a preassigned test num
nels for receiving mark and space pulse information. An
ber in the private line and terminal per line matrix 640
other transducing head comprises an erase head 5503 hav~
so that, in response to operation of the testing means fol
ing a single gap which is adapted to erase the entire
lowing the operation of a manually controlled busy means 03 Dr width or both channels of the magnetic tape.
which prevents seizure of the trunk circuit, an artificial
During recording operations, the magnetic tape is sta
calling line designation is automatically supplied to the
tionary, and the ?rst advancing means comprises a step
trunk circuit and to the trunk recorder 500‘ to'permit the
by-step advancing mechanism including a pawl and
recording of complete data pertaining to a test call.
ratchet drive arrangement driven by an advance magnet
To facilitate an easy understanding of the detached 40 530 for advancing the magnetic tape through a very
contact type of drawings utilized in the following descrip
small distance following the recording of each, pulse. In
tion of an illustrative embodiment of the invention, a
order to provide high speed playback or readout opera
combined numerical and alphabetical designation has been
tions,
a continuous drive mechanism is provided. This
utilized to identify many of the relay structures and
manually operated keys forming the schematic diagram
of the trunk circuit. The windings of the relays are
identi?ed by one or more numerical digits indicating the
?gures of the drawings on which the relay winding is to
be found followed by a group of alphabetical characters
drive mechanism comprises a clutch magnet or solenoid
510 which moves a clutching idler into a position inter
posed between a driving roller and a pinch roller and
capstan type of drive arrangement which directly drives
the magnetic tape. In this manner, during playback op
designating the relay. The contacts pairs of the various 50 erations, the magnetic tape in the trunk recorder 500‘ is
rapidly advanced to produce mark and space impulses
relays in the schematic circuit diagram are designated
which are transmitted through the trunk circuit and the
by a composite alphabetical and numerical designation
playback control circuit 460 to the recording facilities
in which one or more numerical characters identifying
410. A pair of contacts 511 in the energizing circuit
the ?gure of the drawings on which the contact pair is lo
for the magnet 530 are controlled by the clutch magnet
cated is followed by a group of alphabetical characters
510 to prevent step-by~step operation of the magnetic
indicating the relay of which the contacts form a part.
tape during continuous drive operations.
One or more numerical characters are added to this des
In order to provide means for returning the magnetic
ignation to individually designate the different contacts of
tape in the trunk recorder 500 to its effective beginning or
the same relay appearing in a single ?gure of the draw
mgs.
'
As an example, a calling bridge relay having an oper
home position prior to recording and reproducing opera
60 trons and in order to provide an alarm indication when
the magnetic tape in the trunk recorder 500 is ?lled with
ating winding located in FIG. 3 of the drawings is desig
items of information, a pair of tape controlled contacts
nated 3CB, and the contacts of this relay which'are also
501 are provided which cooperate with three spaced per
located in FIG. 3 of the drawings are designated 3CB1
and 3CB2. Two other contact pairs forming a part of 6 forations or conductive portions on the surface of the
magnetic tape so as to de?ne the effective beginning and
this relay appear in FIG. 2 of the drawings and, accord
ingly, are designated 2CB1 and 2CB2 .to indicate the ?rst
end thereof. As disclosed in the above identi?ed Gleason
and second contact pairs of the CB re'lay located in
application, the tape contact structure may comprise por
FIG. 2.
. .
tions carried on the surface of'the tape which selectively
In addition, certain of-the keys forming a part of this
bridge contact ?ngers held in engagement with one sur
schematic diagram, which may be either automatically or
face of the magnetic tape. Alternatively, the tape con
manually operated, are designated by one or more alpha
tact arrangement may comprise a grounded roller and
betical characters identifying the key. 'The contacts on
a contact brush between which the magnetic tape is
,the key are designated by ‘one or more numerical char
interposed so that the brush and roller arrangement sense
acters indicating the ?gure of the drawings on which the 75 spaced perforations in themagnetic tape.
A
3,051,789
9
16
OPERATION OF THE TRUNK CIRCUIT TO RE
CORD INFORMATION IN THE ‘TRUNK RE
CORDER 500
opening of the contacts 2RDS1 interrupts a point at an
open operating circuit for a diiferential end-of-call relay
2EC, and the closure of the contacts 2RDS2 prepares
an operating circuit for a space relay 281). The open—
During recording operations, the trunk circuit, under
the control of dial impulses supplied from the calling
subscriber and answering supervisory signals received
from the calling subscriber, selectively controls the re
ing of the contacts SRDSI opens a shunt including a re
sistor 351 land a condenser 352 which is across the re
peater coil 326. The resistor 351 has a value approxi
mating that of the proper termination resistance for the
cording of items of information pertaining to a toll call
trunk circuit looking into the trunk circuit from the re
on the magnetic tape of the trunk recorder 500. At the
mote
switching equipment 300. The opening of the con
10
termination of the recording operation, an end-of-call
tacts 3RDS3 interrupts an additional point in an open
code is recorded on the magnetic tape of the trunk re
operating circuit for a reset magnet SDCZ of the step
corder 50%), and a stepping switch and a pulsing source
ping switch DC.
cooperate to advance the magnetic tape a predetermined
The concurrent closure of the contacts 3RDS4 com
distance following the last of the recorded items of in
pletes an obvious operating circuit for a slow-to~release
formation pertaining to the preceding toll call.
third release delay relay BRDT so that this relay operates
Referring now more speci?cally to the drawings, as
to close a plurality of contacts ZRDTI, 2RDT3, 2RDT4,
described above, in response to the dialing of an access
and SRDTI and to open a plurality of contacts ZRDTZ,
digit, the calling 3loop circuit is extended from the calling
'4RDT1, and dRDTZ. The closure of the contacts
substation A through the line circuit 100, the ?nder Hi2,
ZRDTT prepares an operating circuit for the end-of-call
and the selector 104 to the trunk circuit shown in FIGS.
relay ZEC, and the opening of the contacts ZRDTZ re
2 to 5, inclusive. This extension of the switch train to
moves ground from a circuit extending through a plu
the trunk circuit completes the calling loop circuit through
rality of closed contacts ZHMZ, ZCSl, and ZBYl and a
the input windings of a repeater coil 32%) and the upper
and lower windings of a calling bridge relay SCB to 25 normally closed switch 235 to ‘a terminal 236 which is
ground through a pair of normally closed contactsi
3TS1 and to grounded battery. The completion of this cir
cuit operates the calling bridge relay SCB to open a
connected to a common supervisory control.
The re
moval of ground from this terminal indicates that the
trunk circuit is in a busy condition. The normally closed
switch 235 is opened by the removal of the trunk record
pair of contacts 3CB1 and to close a plurality of contacts
ZCBZ, 3CB1, and 3CB2. The closure of the contacts 30 er 500 to provide an indication that the trunk circuit is
busy. The closure of the contacts ZRDTS prepares an
3CB1 and 3CB2 and the opening of the contacts ZCBl
operating circuit for the space relay ZSP, and the closure
serve no useful function at this time. However, the closure
of the contacts 2RDT4 prepares another portion of the
of the contacts ZCBZ completes an obvious operating cir
operating circuit for the mark relay SMK and the motor
cuit for a release delay relay 2RD so that this relay
operates to open a plurality of contacts 2RD1 and 4RD1 35 magnet 313C of the stepping switch DC. The closure
of the contacts 3RDT1 provides an additional source
and to close a plurality of contacts 2RD2, 2RD3, 3RD1,
of holding ground for the sleeve lead of the extended
SRDZ, and 3RD3.
switch train, which ‘ground is interrupted at the open
The closure of the contacts 3RD1 applies ground to
contacts 3RDS2. The opening of the contacts 4RDT1
the sleeve lead of the extended switch train, thereby to
hold the switch train operated and to indicate that the 40 interrupts a point in an operating circuit for a home re
lay 4HM, thereby to prevent the operation of this relay
trunk circuit is busy. The opening of the contacts 4RD1
during a data recording operation. The opening of the
further opens an interrupted path for initiating an
contacts 4RDTZ performs no useful function ‘at this
emergency playback operation of the trunk circuit by
time.
the playback control circuit 400. The closure of the
The trunk circuit, in response to the seizure thereof,
contacts 3RD2 interconnects a timer motor 360‘ to a ter 45
has operated the calling bridge relay 3GB and the re
minal 361 which is provided with a suitable energizing
lease delay relays ZRD, ZRDS, and 3RDT to prepare
voltage, thereby to condition the timing means individ
pulsing paths for the space relay ZSP, the mark relay
ual to the trunk circuit for operation. The closure of
3MK, and the motor magnet of the stepping switch 3DC
the contacts 3RD3 completes a circuit including the con
to
provide holding ground for the extended switch train
tacts 3SHS3, 3NI2, SCBI, 0r 3PT1, 3SHS4, 3RD3, and
and to provide busy ground to prevent additional at
3PT2 or 3CB2 for placing the right hand operating wind
tempted seizure of the trunk circuit by the circuit 4%
ing of the differential supervisory relay 38R across the
or the telephone switching means. The trunk circuit is
outgoing tip and ring conductors of the trunk circuit.
now
conditioned to receive the ?rst dialed information
Further, the closure of the contacts 2RD2 energizes the
left hand winding of the relay 35R, but the supervisory 55 from the substation A which simultaneously operates
the stepping switch DC ‘and is recorded in the trunk re
relay 35R is not operated at this time. The closure of
corder 5% but which is not repeated over the outgoing
the contacts 2RD3 prepares an operating circuit for a
lines of the trunk circuit to the remote switching equip
mark pulse relay 3MK and a motor magnet SDC of a
ment 300.
stepping switch DC, and the opening of the contacts
The first item of information which is dialed by the
60
2RD1 performs no useful function at this time.
calling subscriber at the station A following the seizure
The closure of the contacts ZRDZ also provides a
of the trunk circuit is a party digit which, as explained
source of main holding ground for the trunk circuit and
above, is of arbitrary value for calls placed from pri
completes an obvious operating circuit for a release de
vate lines, forms the units digit of the directory number
lay slave relay ZRDS which operates to open a plurality
for calling substations on terminal per line multiparty
65
of contacts ZRDSI, 3RDS1, SRDSZ, 3RDS3, and 4RDS2
lines, and is utilized to selectively position the stepping
and to close a plurality of contacts 2RDS2, 3RDS4, and
switch DC to provide information for subsequently con
4RDS1. The closure of the contacts 4RDS1 grounds a
trolling the operation of the party matrix switching cir
conductor 403 to prevent seizure of the trunk circuit
cuit ‘690 if the calling substation A is located on a ter
during a data recording operation, and the concurrent 70 minal per station multiparty line. Accordingly, when
opening of the contacts é-RDSZ performs no useful func
the calling loop circuit extending to the trunk circuit is
tion at this time. The opening of the contacts 3RDS2
?rst interrupted incident to trans-mission of the ?rst im
further interrupts one open circuit for supplying ground
pulse of the dialed party digit, the calling bridge relay
to the trunk sleeve terminal or conductor, ground re
3GB releases to close the contacts 2CB1 and to open
maining thereon at the closed contacts SRDT. The 75 the contacts ZCBZ, 3CB1, and SCBZ. The operations
3,051,789
12
11
ing’ the resistance in the pulsing circuit for the‘calling
bridge relay SCB. The opening of the contacts 3SH2 in
of the contacts 3CB1 and 3CB2 produce no useful func
tion inasmuch as these contacts are shunted by the closed
contacts 3PT1 and 3PT2. 'The' opening of ‘the contacts
terrupts ‘an additional point in the circuitfor applying
ground to the wipers 2DC1, 2DC2, and 2DC3 of the step
ping switch DC, and the concurrent closure of the con
2CB2 interrupts the above described operating circuit
for the release delay relay 2RD, but this relay is slow
tacts 3SH3 prepares an operating circuit for the motor
magnet 3DC of the switch DC. The opening of the con
tacts 2SH1 interrupts a point in an operating circuit for
to-release and does not release at this time.
a The closure ‘of the contacts 2CB1 applies ground
through a circuit including the closed contacts 2SRS2,
2LD3, 2RD3, 2RDT4, 2IC5, 2PU4, and 3SD1 to be ap
the space relay 281’.
The closure of the contacts SSHI completes an obvi
ous operating circuit for a shunt slave relay SSHS which,
plied to the operating winding of the mark relay SMK,
thereby operating this relay to close two pairs of contacts
4MK1 and 5MK1. The closure of the contacts 4MK1
in operating, closes a plurality of contacts ZSHSI, 2SHS2,
forwards ground over a circuit including the closed con
SSHSI, 3SHS2, and 381-185 and opens a plurality of con
tacts 3SHS3, 3SHS4, and 3SHS6. The closure of the
tacts 4MKS1, 4MK1, 4CS13 to be applied to the operat
ing winding of the mark pulse head 52-9, the other side of
which is connected to grounded battery through a pair
of normally closed contacts 4CS11. The completion of
this circuit energizes the mark pulse head 529 to record
a mark or information pulse on the mark pulse channel
of the magnetic tape in the trunk recorder 5430 repre
senting the ?rst pulse of the dialed party digit. The
closure of the contacts SMKI completes an obvious op
erating circuit ‘for a second mark pulse relay SMKS which
operates to open the contacts 4MKS1 and to close a pair
of contacts 4MKS2. The opening of the contacts 4MKS1
contacts 2SHS1 prepares a circuit for applying ground to
the wipers ZDCl, 2DC2, and 2DC3 of the stepping switch
DC, which circuit is interrupted at the open contacts
3SH2.
interrupts the above described circuit for energizing the
mark pulse head 520, thereby terminating the recording of
the ?rst mark pulse in the trunk recorder 500. The con
current closure of the contacts é-MKSZ completes an
operating circuit for the ratchet magnet 530 extending
from ground through the closed contacts 4MKS2, 5PA1,
and 563, and the winding of the magnet 530 to grounded
battery through a pair of contacts 511 controlled by the
clutch magnet 510. The energization of the magnet 530
conditions the step-by-step driving mechanism in the trunk
recorder 5% for advancing the magnetic tape a single
step following the recording of the mark pulse thereon.
Referring to the above described circuit for operating
the mark relay 3MK, the ground extended to the operat
ing winding thereof in response to closing the contacts 40
ZCBI is also extended through a plurality of closed con
tacts 3EC2 and 3PT4 to energize the motor magnet 3DC
of the stepping switch DC so that a plurality of wipers
2DC1, 2DC2, 2DC3, and 2DC4 are advanced, the switch
DC being of the direct acting type. In moving to the
?rst stepping position in the bank of contacts adjacent
thereto, the wiper 2DC1 prepares an operating path for
a party one relay 2ON, which is one of a group of four
party digit register relays including a group of other
register relays 2T0, ZTR, and ZSTT. However, the op- >
erating circuit for the party one relay 2ON is not com
pleted at this time inasmuch as ground is not ‘supplied to
any of the wipers 2DC1, 2DC2,’or ZDCS. Thus the step
ping switch DC is advanced a single step in synchronism
with the recording of a single mark pulse on the‘ magnetic
The closure of the contacts ZSHSZ prepares a
portion of an operating circuit for the 'space relay 2SP,
which circuit is interrupted at the open contacts 281-11.
The closure of the contacts 3SHS1 applies a shunt around
one of the operating windings of the supervisory relay
35R, and the opening of the contacts 3SHS3 and 331-184
disconnects this winding of the supervisory relay from
25 the pulsing paths extending to the conductors of the trunk
circuit. The closure of the contacts 3SHS2 connects
grounded battery to one of the leads of the trunk circuit
through a circuit including the closed contacts 3NI2 and
3PT1, and the concurrent closure of the contacts 3SHSS
connects ground to the other of the conductors of the
trunk circuit through a circuit including the closed con
tacts SRDS and 3PT2. The opening of the contacts
3SHS6 interrupts a point in an operating circuit for the
‘release magnet 3DCZ.
' At the end of the ?rst open circuit interval represent
ing the ?rst pulse or the dialed party digit, the calling
bridge relay 3GB again operates to close and open the
contacts controlled thereby so that the contacts 3CB1
and 3CB2 connected in the signaling path of the trunk
circuit are again closed, but the closure thereof has no
effect due to the closed contacts 3PT1 and 3PT2. The
closure of the contacts 2CB2 again completes the operat
ing circuit for the slow-to-release release delay relay 2RD
which is maintained operated during the release interval
of the calling bridge relay 3GB. The opening of the
contacts 2CB1, however, interrupts the above described
opening circuit for both the motor magnet 3DC and the
mark relay 3MK, thus permitting the magnet 3DC to
release in preparation for the next operation thereof.
The release of the mark relay SMK opens the contacts
fiMKl and SMKI. The opening of the contacts 4MK1
interrupts, at an additional point, the previously inter
rupted circuit for energizing the mark pulse head 520,
and the opening of the contacts SMKI interrupts the op
tape in the trunk recorder 5%!) in response to the trans
erating circuit for both the shunt relay SSH and the sec
ond mark pulse relay SMKS. The shunt relay SSH,
mission of the ?rst impulse of the dialed party digit.
however, is slow-to-release and does not release at this
The operation of the motor magnet 3DC also opens a
time.
However, the second mark pulse relay SMKS does
pair of interrupter contacts 2DC5, but this produces "no
useful function at this time. In advancing, the wipers 60 release to close the contacts 4MKS1 and to open the
ZDCl-ZDCé- close a plurality of off-normal contacts
3DC1 and 3DC2. The closure of the contacts 3DC1 pre
pares an operating circuit for the reset or release magnet
3DCZ, and the closure of the contacts 3DC2 prepares an
contacts 4MKS2.
The closure of the contacts 4MKS1
prepares the above described pulsing path for the mark
pulse head 52!}, and the concurrent opening of the con
tacts 4MKS2 interrupts the above described operating
additional circuit for applying ground to the Isleeve termi— 65 circuit for the drive magnet 530, thereby permitting this
magnet to release and to advance the magnetic tape in
'
the trunk recorder 500 a single step. According, at the
Referring back to the closure of the contacts SMKl in
end of the ?rst pulse of the dialed party digit, the stepping
response to the operation of the mark relay 3MK, the
switch DC has been ‘advanced a single step, a single
ground provided thereby is extended through a plurality
mark pulse has been recorded on the magnetic tape in
of closed contacts SECI and 5LD1 to complete an obvious
the trunk recorder 500, and this magnetic tape has been
operating circuit ‘for a slow-to-release shunt relay SSH
advanced ‘a single step, the ?rst pulsetransmitted to the
which, in operating, opens a plurality of contacts 281-11 ,
trunk circuit further causing the operation of the shunt
and 3SH2 and closes a plurality of contacts 3SH1, 33113,
relay SSH and the shunt slave relay 'SSHS.
and SSHI. The closure of the contacts 3SH1' shunts the
uppermost winding of the repeat coil 321')‘, thereby reduc 75 During the receipt of subsequent impulses in the series
nal of the trunk circuit.
3,051,789
13
14
of impulses representing the value of the dialed party
net 530, thereby to condition the magnetic tape for being
advanced a single step.
Referring back to the preceding release of the shunt
relay SSH, the closure of the contacts 3SH2 in response
to release of this relay completes an obvious circuit for
extending ground through a plurality of closed contacts
2PT4 and 2SHS1 to the wipers *2DC1, ZDCZ, and 2DC3
which, as described ‘above, are in engagement with the
train. Assuming that the calling substation A is located
tenth contacts in the contact banks associated therewith,
on a terminal per station multiparty line and is assigned 10 thus representing the value of the dialed party digit as
digit, the trunk circuit operates, as described above, to
record additional mark puiscs on the mark pulse chan
nel of the tape in the trunk recorder 5G0 and to advance
this tape a single step at the termination of the recording
of each of these pulses. Further, the stepping switch
DC is advanced a single step in response to each impulse
received by the trunk circuit from the extended switch
the tenth position thereon, the assigned party digit is “0”
being “10.” The ground applied to the wipers 2DC1,
2DC2, and 21303 is simultaneously extended to the op
erating windings of the party two relay 2T0 through a
normally closed pair of contacts 2TO2, to the operating
times during which ten mark pulses are recorded on the 15 winding of ‘the party three relay ZTR through a pair of
magnetic tape in the trunk recorder 500, ‘and this mag
normally closed contacts 2TR2, and to the operating
Winding of the parties six-ten relay ZSTT through a pair
netic tape is advanced ten steps. Further, the wipers
of normally closed contacts ZSTTZ, thereby causing the
ZDCl, 2DC2, 2DC3, and 2DC4~ of the stepping switch
DC are advanced ten steps so that these wipers engage
simultaneous operation of these three relays. The con
the last contacts in the contact banks associated therewith. 20 current operation of these relays provides a manifestation
1n the interdigit interval following the dialing of the
or representation ‘of the value of the dialed party
dialed party digit, the trunk circuit conditions the sig
digit “10.”
nailing circuit therein for extending switch directing im
The operation of the party two relay 2T0 closes a
pulses over the output conductors of the trunk circuit
plurality of contacts ZTOl, 2-TO4, 2TO6, 2TO7, and
to selectively operate the remote switching equipment 25 3TO1 and opens a plurality of contacts 2TO2, 2TO3,
and, accordingly, a series of ten open circuit intervals
in the calling loop circuit is provided so that the calling
bridge relay 30B operates and releases ten successive
‘309 so as to establish a connection to the called substation
B, produces the operation of one or more of the party
and 2TO5. The contacts ZTOl and 2TO2 form a make
before-break contact arrangement so that the contacts
digit register relays ZON, 2T0, IZTR, and 2STT in ac
2TO1 complete ‘a circuit extending to holding ground
cordance with the Value of the dialed party digit, re
at the closed contacts ZRDZ through a pair of normally
stores the stepping switch DC to its normal position, 30 closed contacts 2IC1 prior to the opening of the con;
and records a control or space impulse on the magnetic
tacts ZTOZ to interrupt the above described operating
tape of the trunk recorder ‘50% immediately following the
circuit for the relay 2T0. The selective operation of
group of mark pulses representing the value of the dialed
the contacts 2TTO3 to 2TO6, inclusive, partially prepares
party digit, thereby to separate the record of the dialed
a marking path to one of ?ve conductors designated "1
party digit on the magnetic tape from the record per 35 or 6,” “2 or 7,” "3 or 8,” “4 or 9,” and “5 or 10” in FIG.
taining to the next dialed digit. More speci?cally, in the
6 of the drawings, which conductors extend to the party
interdigit interval following the dialing of the party digit,
matrix switching circuit 600. The closure of the contacts
the slow-to-release shunt relay SSH releases to close the
2TO7 prepares an operating circuit for a party transfer
contacts 2SH1 and 351-12 and to open the contacts 3SH1,
relay ZPT, and the closure ‘of the contacts l3TO1 prepares
351-13, and 581-11. The opening of the contacts 381-13 40 an operating circuit for the release magnet BDCZ of the
again interrupts the partially prepared operating circuit
stepping switch DC.
for the motor magnet 3DC of the stepping switch DC.
The operation of the party three relay 2TR closes a
The opening of the contacts SSHl interrupts the operat
ing circuit for the shunt slave relays SSHS, but this relay
plurality of contacts ZTRI, 2TR4, 2TR5, and 3TR1, and
is rendered slow-to-release by a circuit including a resis
tor 521 and a condenser 522 in parallel with the operat
ing winding of the relay SSHS, and, accordingly, the
opens a plurality of contacts 2TR2 and 2TR3. The con
45 tacts 2TR1 and 2TR2 form a make-before-break contact
arrangement in which the closure of the contacts 2TR1
completes a holding circuit for the relay 2TR extending
shunt slave relay SSHS does not release at this time.
to ground through the closed contacts ZICI and 2RD2
The opening of the contacts 3SH1 removes the shunt
prior to the opening of the contacts ZTRZ to interrupt
around the upper winding of the repeat coil 320, and 50 the above described operating circuit for the relay ZTR.
the closure of the contacts ZSHI completes an operating
The opening ‘of the contacts ZTRS interrupts the partially
circuit for the space relay 2SP extending from closed
prepared path extending to the conductor designated “2
and grounded contacts 2RDT3 through the closed con
or 7” by the closure of the contacts 2TO4, and the con
tacts 2SHS2, 251-11, 2PU6, and 2SD2 to the operating
current closure of the contacts 2TR4 prepares a marking
55 path extending through the closed contacts ZTOG'to the
winding of the relay ZSP.
The operation of the relay ZSP closes a plurality of
conductor designated “5 or 10,” thus indicating that the
contacts 3SP1 and 4SP1. The closure of the contacts
4SP1 completes a series circuit including the closed con
tacts 4SPS1, 4SP1, 4CS17, the operating winding of the
value of the stored party digit is either “5” or “10” in
accordance with the operated or released condition of the
parties six-ten relay ZSTT. The closure of the contacts
and grounded battery.
space pulse head 540, a pair of closed contacts 40815 60 2TR5 prepares a circuit in parallel with the closed con
The completion of this circuit
tacts 2TO7 for operating the party transfer relay 2PT.
energizes the space pulse head 540 to record a space
pulse on the space pulse channel of the magnetic tape
The closure of the contacts 3TR1 provides a source of
the contacts 4SPS1 ‘and closes a pair of contacts 4SPS2.
arrangement so that the closure of the contacts ZSTTl
operating ground which is parallel to that provided by the
in the trunk recorder 500 immediately following the last 65 closed contacts 3TO1 in the partially conditioned op
erating circuit for the release magnet 3DCZ.
of the group of ten recorded pulses thereon representing
The operation of the parties six-ten relay ZSTI' closes
the value of the dialed party digit. The closure of the
a
plurality
of contacts 2STT1 and 2STT4 and opens a
contacts ‘3SP1 completes an obvious operating circuit
plurality of contacts 2STT2 and 2STT3. The contacts
for a second space relay 3SPS which, in operating, opens
2STT1 and 2STT2 form a make-before-break contact
The opening of the contacts 4SPS1 interrupts the above
completes a holding circuit extending to ground through
described energizing circuit for the space head ‘540, there
the closed contacts 2101 and 2RD2 prior to the opening
by to terminate the recording of the space pulse, and
of the contacts 2STT2 to interrupt the above described
the concurrent closure of the contacts 4SPS2 completes
operating circuit for the relay ZSTT. The opening of the
the energizing circuit described above for the drive mag 75 contacts ZSTTS indicates that the valuerof the stored
3,051,7ea
15
apply girouhd to a ‘terminal 435 through a parallel combi
party dig-it is not in the range of the digits “1” to "5” by
opening an operating path for a one-to-?ve relay GOTF
in the matrix 'switc-hing‘circuit 600, and the concurrent
nation of a resistor 407 and an alarm lamp 406. The
continuous maintenance of ground on the terminal 405
closure of the contacts 2STT4 prepares a circuit for op
provides delayed illumination of the lamp 406 to pro—
erating an above ‘?ve relay 6AF, thereby to indicate that
one of the two digits represented by the selection of the
vide a visible indication in the event that the release
magnet 3DCZ is not released within a selected period of
time.
conductor designated as “5 or 10” is in the range above
“5” or has the value of “10.”
Although the operation of the party one relay 2ON
has not been described‘ in detail, this relay is operated by
the stepping switch DC when the value of the stored
party digit is “1,” “4,” “6,” or “9” to actuate a plurality
of contacts 2ON1, 2ON2, 2ON3, 2ON4, ZONE, 2ON6,
In restoring the wipers 2DC1, 2DC2, 2DC3, and 2DC4
of the stepping switch DC to their normal home posi
tions, the off-normal contacts 3DCZ are opened, which
perform no useful function, and the contacts 3DC1 are
opened to release the release magnet 3DCZ so as to open
the contacts 4DCZ1. The restoration of the wipers
2DC1-2DC4 to their home positions also completes an
and 3ON1 to perform substantially the same functions as
the operation of the relays 2T0 and ZTR. Accordingly, 15 operating circuit for the party transfer relay ZPT extend
ing from closed and grounded contacts 3SH2 over the
the selective operation of one or more of the group of
wiper 2DC4 and through the closed contacts 2TO7 and
party digit register relays ZON, 2T0, 2TR, land ZSTT
2TR5 in parallel and a pair of normally closed contacts
establishes partially prepared circuits extending to the
2PT1. The completion of this circuit operates the party
party matrix switching circuit 600 in accordance with the
value of the stored party digit on one of ?ve conductors, 20 transfer relay ZPT to indicate the completion of the
operations of the trunk circuit in which the party digit is
each of which represents a digit equal to or less than “5”
stored in the party digit register relays ZON, 2T0, ZTR,
and a digit greater in value than “5.” The relay ZSTT
and 2STT and in which the value of this digit is stored
also prepares a circuit on one of two conductors extend
in the trunk recorder 500. In operating, the party trans
ing to the switching circuit 600 in accordance with
whether the registered digit has a value equal to or less 25 fer relay ZPT conditions the trunk circuit to repeat the
next dialed digits from the switch train over the trunk
than “5” or more than “5,” thereby to prepare the switch
conductors to the remote switching equipment 300, thereby
ing circuit 600 for selecting a single control component
to establish a connection to the calledsubstation B. The
or party matrix in accordance with ‘the register value of
the party digit. The relays ZON, 2T0, and ZTR also
prepare operating paths for the reset magnet 3DCZ and
the party transfer relay 2PT.
Following a suitable time interval sufficient to cover
the above described’ operations, the shunt slave relay
SSHS, the operating circuit for which was interrupted by
the release of the shunt relay SSHS, releases to open the
Contacts ZSHSl, v2SHS2, SSHSI, 3SHS2, and 3SHS5 and
to close the plurality of contacts 3SHS3, 331-184, and
3SHS6. The contacts 3SH7S1 remove the shunt around
the Winding of the supervisory relay 378R, while the
closure of the contacts SSHSS and 3SHS4 interconnects
‘this winding of the relay 38R with the line conductors
of 'the trunk circuit. The opening of the contacts 381-185
and 381-182 disconnects ground and grounded battery
from the liner conductors of the trunk circuit. The open
ing of the contacts ZSHSI interrupts the above described
circuit ‘for ‘supplying ground to the wipers 2DC1, 2DC2,
and 2DC3'of the stepping switch DC.
The opening of the contacts 2SHS2 interrupts the above
described operating ‘circuit {for the space relay. ZSP so
that this'r'elay releases to open the contacts 3SP1 and
4SP1. The opening of the contacts 4SP1 ‘interrupt-s at an
party transfer relay further conditions the stepping
switch DC to count the number of dialed digits to pre
vent the transmission of super?uous digits to the trunk
recorder 500 and over the trunk circuit to the remote
switching equipment 300.
The operation of the party transfer relay closes a plu
rality of contacts ZPTZ, 2PT3, 3PT3, and 5PT1 and opens
a plurality of contacts 2PT1, ZPT4, 3PT1, 3‘PT2, 3PT4,
and 3PT5. The contacts 2PT1 and 2PT2 form a make
before-break contact arrangement so that the closure of
the contacts 2PT2 completes a holding circuit to the
closed and grounded contacts ZRDZ prior to the opening
of the contacts 2PT1 to interrupt the operating circuit
for the party transfer relay 2PT. The opening of the
contacts 2PT4 interrupts, at an additional point, the
above described circuit for applying ground to the wipers
2DC1, 2DC2, and 2DC3. The closure of the contacts
2PT3 prepares ‘an operating circuit for a last digit relay
2LD extending to the seventh contact in the contact bank
engaged by the Wiper 2DC4, thereby preparing the last
digit relay 2LD for operation following the transmission
of seven digits over the extended switch train to the trunk
3SP1 interrupts the operating circuit for the second space .
circuit. The opening of the contacts 3'PT1 and 3PT2
conditions the signaling circuit in the trunk circuit for
operation by. the contacts 3CB1 and 3CB2 controlled by
the calling bridge relay 3GB so that dial pulses transmit
relay 3SPS so that this relay releases to close the contacts
4SPS1 and to open the contacts 4SPS2.. The closure of
ductors to the remote switching equipment 300.
additional point the above described operating circuit for
the space pulse ‘head 540, and the openingof the contacts
ted to the trunk circuit are repeated over the trunk con
The
the cont-acts 4SPS1 prepares the above‘ described operating
circuit ‘for the space pulse head 540, and the opening of
closure of the contacts 3PT3 prepares an operating cir
the contacts 4SPS2 interrupts the above described operat- .
DC so that this switch is enabled to count the digits trans
the drive mechanism to advance the magnetic tape in
and the concurrent opening of the contacts 3PT4 inter
cuit for the motor magnet 3DC of the stepping switch
ing circuit for the drive magnet 530, thereby permitting 60 mitted to the trunk circuit from the calling substation A,
rupts the above described operating circuit for the motor
magnet 3DC. The opening of the contacts 3PT5 inter
ing of the space pulse thereonr '
'
rupts, at an additional point, the operating circuit for
Referring back torthe'above described release of the .
shunt slave relay SSHS, the closure of the contacts 3SHS6 65 the reset magnet 3DCZ’. The closure of the contacts
the trunk recorder 500 a single step following the record
completes an operating circuit for the release magnet
3DCZ of the stepping switch DC extending from ground
' at either of the closed contacts 3TO1 or 3TR1 through
5PT1 prepares an operating circuit for a clock-calendar
relay SCC. ,The trunk circuit is now conditioned to
receive the series. of pulses representing the directory
the closed contacts 3SHS6, 3PT5, and the closed oif- . number of the called subscriber B.
normal contacts 3DC1 of the stepping switch DC. In 70 Assuming that a conventional “21-5” numbering scheme
‘response to energization of the magnet 3DCZ, the wipers
‘ZDCI, _2DC2, 2DC3, and 2_DC4 are mechanically re
turned to their normal position illustrated in FIG. 2 of
is utilized, the calling bridge relay 3GB is released in re
sponse to the ?rst calling loop circuit interruption pro
duced by dialing the ?rst digit identifying the called sub
station B, thereby to close the contacts 2CB1 and to
also closes a pair of release magnet springs 4DCZ1 to 75 open the contacts 2CB2, 3CB1, and 3CB2. The open~
the drawings. 'The energization of the magnet 3DCZ .
3,051,789‘
18
17
ing of the contacts 3CB1 and 3CB2 produces no useful
function at this time, and the opening of the contacts
2CB2 again interrupts the operating circuit for the re
lease delay relay 2RD which does not release at this
time due to the slow-to-release characteristic thereof.
The closure of the contacts 2CB1 sequentially operates
the mark relay SMK, the second mark relay SMKS, the
shunt relay SSH, and the shunt slave relay SSHS, as de
open the contacts 3SH3 so as to interrupt the above de- '
scribed operating circuit for the motor magnet 3DC of
the stepping switch DC. The switch, in releasing, again
closes the interrupter contacts ZDCS which produces no
useful function at this time. Further, as described above,
the sequential release of the shunt relay SSH and the
shunt slave relay SSHS in closing the contacts 2SH1 and
in opening the contacts ZSHSZ momentarily energizes the
scribed above, so as to momentarily energize the mark
space relay 28F and the second space relay 3SPS so that
pulse head 520 to record a single mark pulse on the 10 a single space pulse is recorded on the magnetic tape of the
magnetic tape of the trunk recorder 50%) and to energize
trunk recorder 500 immediately following the ?rst digit
the drive magnet 530 to condition the magnetic tape for
in the designation of the called subscriber B.
a single step of advancement.
In this manner, the calling bridge relay 3CB, the ?rst
The sequential operation of the shunt relay SSH and
and second mark relays 3MK and SMKS, the ?rst and
the shunt slave relay SSHS produces the same functions
second space relays ZSP and 3SPS, the shunt relay SSH,
described above with the following exception. The clos
the shunt slave relay SSHS, and the motor magnet SDC
ure of the'contacts 3SHS2 and 3SHS5 extends grounded
operate during the next six digits transmitted over the
battery and ground to the now open contacts 3CB1 and
extended switch train to the trunk circuit to record the
3CB2 controlled by the calling bridge relay 3CB in prep
values of these digits on the magnetic tape in the trunk
mation for providing ground and battery for pulsing the 20 recorder 50%} in the form of groups of mark pulses includ
conductors of the trunk circuit extending to the remote
ing pulses equal in number to the value of the digit. The
switching equipment 300. The closure of the contacts
dial pulses are further repeated over the trunk circuit to
3SH3 completes the energizing circuit for the motor mag
the remote switching equipment 301} to control the estab
net 3DC so that the contacts 2DC5 are opened and the
lishment of a switch train to the called subscriber B in the
wipers 2DC1, 2DC2, 2DC3, and 2DC4 are advanced to 25 remote area. Concurrently therewith, the shunt relay
SSH sequentially advances the stepping switch DC so that
the ?rst contacts in the contact bank associated therewith,
thereby representing the dialing of the ?rst digit of the
the wipers ZDCl, 2DC2, 2DC3, and 2DC4 thereof are
c?ed subscriber designation. The opening of the con
advanced over the contacts engaged thereby so that, at
tacts 2DC5 produces no useful function at this time. In
the completion of the transmission of this sixth additional
‘advancing the switch DC off-normal, the oif-normal con
‘digit, or the seventh digit, the wiper ZDC4, together with
tacts 3DC1 and 3DC2 are closed. The closure of the
the other wipers in the switch DC, are positioned in en
contacts 3DC1 prepares an operating circuit for the re
gagement with the seventh contact in the contact bank
lease magnet SDCZ, which is now interrupted at the open
associated therewith. In this position, the wiper 2DC4
contacts 3PT5, and the closure of the contacts 3DC2
is connected to the operating winding of the last digit
again provides a source of holding ground for the sleeve 35 relay 2LD through a circuit including the closed pairs of
lead of the extended connection, which ground is ineffec
contacts 2PT3 and 2LD1. The selective operation of the
tive due to the open contacts 3RDS2.
last digit relay informs the trunk circuit that the proper
When the calling bridge relay SCB is again operated
complement of digits necessary for extending a con
in response to reclosure of the calling loop circuit at the
nection to a remote subscriber, such as the called sub
calling substation A, the contacts 2CB2, 3CB1, and 3CB2
station E, has been both transmitted and recorded in the
are closed, and the contacts 2CB1 are opened. The open
trunk recorder 59%, and, accordingly, the last digit relay
ing of the contacts 2CB1 releases the mark relay 3MK
provides means for preventing the storing of additional
and the second mark relay SMKS to permit the magnet
digits in the trunk recorder 504} and for likewise prevent
530 to release and thus advance the magnetic tape in the
ing the transmission of additional information over the
recorder 500 a single step following the recording of the 45 trunk circuit to the remote switching equipment 300.
?rst mark pulse representing the value of the first dialed
More speci?cally, in the interdigit interval following
digit of the called subscriber designation. The closure
the dialing of the last of the seven digits dialed to obtain
of the contacts 2CB2 again completes the operating cir
access to the called substation B, the shunt relay SSH
cuit for the release delay relay 2RD. The closure of the
releases, as described above, and in doing so closes the
contacts 3CB1 and 3CB2 applies grounded battery and 50 contacts 3SH2 to complete an operating circuit for the
ground, respectively, to the conductors of the trunk cir
last digit relay ZLD extending over the wiper 2DC4
cuit extending to the remote switching equipment 300‘,
through the seventh contact in the bank associated there
thereby to provide a ?rst switch directing pulse to con
with and the closed contacts 2PT3 and 2LD1. Concur
trol the switching equipment 300 in establishing a con
rently therewith, the closure of the contacts 251-11 com
nection to the called substation B.
pletes the above described operating circuit extending
When the calling bridge relay 3GB is next released in
to the space relay 2S1J so that this relay and the second
response to a line interruption, the contacts ZCBll are
space relay 3SPS sequentially operate to record ‘a space
again closed to sequentially operate the mark relay 3MK
pulse on the tape in the trunk recorder 50% immediately
and the second mark relay SMKS to record a second
following the seventh dialed digit of the called sub
pulse on the magnetic tape in the trunk recorder ‘500 and to 60 soriber designation and to energize the drive magnet 530
energize the drive magnet 530 in preparation for advanc—
to condition the magnetic tape for a single step of ad
ing the magnetic tape a single step. Further, in operat
ing, the contacts 3GB! and 3CB2 are again opened to
vancement.
In operating, the last digit relay closes a plurality of
remove grounded battery and ground, respectively, from
contacts 2LD2, 3LD1, and 3LD2 and opens a plurality
the conductors of the trunk circuit to terminate the ?rst 65 of contacts 2LDl, 2LD3, and 5LD1. The contacts
pulse supplied to the remote switching equipment 300.
This intermittent operation and release of the calling
ZLDl
and 2LD2 form a make-before-break contact
arrangement in which the closure of the contacts 2LD2
bridge relay 3CB continues until such time as the series
completes a holding circuit for the relay 2LD extending
or group of pulses representing the value of the ?rst
to the closed and grounded contacts ZRDZ prior to the
dialed digit has been transmitted to the remote switching 70 opening of the contacts 2LD1 to interrupt the above de
equipment 300 and also recorded on the magnetic tape
scribed operating circuit for this relay. The opening of
in the trunk recorder 500.
the contacts 2LD3 interrupts the above described pulsing
In the interdigit interval following the completion of
path for the mark relay 3MK and thus prevents further
the transmission of this group of impulses, the shunt
pulsing of the calling bridge relay 3CB from controlling
relay SSH releases after its slow~to-release interval to 75 the recording of information in the trunk recorder 500.
3,051,789
19'
visory relay 38R is released to releasethe second super-'
visory relay 3SRS before the completion of the timing
The closure of the contacts 3LD1 and 3LD2 provides a
shunt ‘around the contacts, 3CB1 and 3CB2 controlled ‘by
the calling bridge relay 3GB and thus prevents the trans
mission of additional pulse information to the remote
out of the control timing interval provided by the con
tacts 231. The release of the second supervisory relay
switching equipment 300. The opening of the contacts
5LD1 interrupts the above described operating circuit
3SRS opens the contacts 2SRS1 to terminate energiza
tion of the timer clutch 230 so that the cam arrangement
forming a portion of this timer is immediately restored to
a normal condition. Thereafter, the supervisory relays
38R and 3SRS and the timer clutch 230 are intermittently
clock and calendar information and other items of in
formation, such as the designation of the calling sub 10 operated and releasedrin accordance with the busy ?ash
ing supplied to the supervisory relay 3~SR from the re
station A, does not produce an accompanying operation
mote switching equipment 300.
of the shunt relay SSH and the shunt slave relay SSHS.
This intermittent operation continues until such time
The next item of information received by the trunk
as the subscriber at the calling substation A, in response
circuit is supplied from the remote area over the trunk
circuit and comprses either reverse battery answering 15 to the receipt of busy tone, opens the calling loop circuit
to release the calling bridge relay 3GB, the party transfer
supervisory signals or a reverse battery ?ashing indicating
relay ZPT, the last digit relay ZLD, and the release delay
a busy condition. The supervisory relay 35R, which is
relays 2RD, ZRDS, and 3RDT and to restorethe stepping
connected across the conductors from the trunk circuit
switch DC to its normal position. Incident to these
through the closed contacts 351-153 and 351-154 and 3LD1
operations and as described in detail hereinafter, the step
and 3LD2 responds to these signals either to prevent the
ping switch DC cooperates with a pulse assist relay ZPA
recording of additional information, in the event that a
and an end-of-call relay ZEC to provide a measured or
busy tone is received, or to provide an indication that the
counted number of steps of advancement of the magnetic
necessary additional items of information pertainingrto
tape in the trunk recorder 500 immediately following the
the toll call are to be recorded, in the event that answering
recording of an end~of-call code representing the end of
reverse battery supervision is received.
25. the items of information pertaining to the incomplete call.
Assuming that busy signals are recevied by the trunk
The measured run-off of the magnetic tape provides a
circuit indicating that the connection cannot be com
space between the items of information pertaining to this
pleted to the called subscriber B, the supervisory relay
incomplete
call and those pertaining to the next call
33R is operated to close a pair of contacts 3SR1 which
placed through the trunk circuit.
completes an obvious operating circuit for a second super 30
However, assuming that steady reverse battery answer
visory relay 3SRS extending to the closed and grounded
ing
supervisory signals are received by the trunk circuit
contacts 2RD2. The operation of the second supervisory
from
the remote switching equipment 300, the supervisory
relay SSRS closes a pair of contacts 2SRS1 and opens a
relay 35R and the second supervisory relay 3SRS are
pair of contacts ZSRSZ. The opening of the contacts
ZSRSZ interrupts an additional point in the above de 35 operated, as described above, to close the contacts S‘SRI,
2SRS1, and to open the contacts 2SRS2. The closure of
scribed pulsing circuit extending to the mark relay SMK
the contacts ZS'RSl energizes the timer clutch 230 so that
which is controlled by the contacts 2CB1. The closure of
the cam arrangement is advanced under the control of the
the contacts 2SRS1 forwards ground from the closed
timer motor 230 to close the contacts 231 after an inter»
contacts 2RD2 to the operating winding of a timer clutch
of between one to two seconds. The closure of the
230 forming a portion of the timing mechanism whose 40 val
contacts 231 completes an obvious operating circuit for a
drive motor 360 was previously energized by the closure
third supervisory relay Z'SRT extending to the closed and
of the contacts 3RD2. This timing mechanism, which is
grounded contacts 2RD2 through a pair of closed con
individual to the trunk circuit, preferably is of the type
tacts 2SRT3. The operation of the third supervisory re
disclosed in the copending application of Armistead Whar
lay 25R indicates the satisfactory completion of the busy
ton, Serial No. 497,760, ?led March 29, 1955, which ap 45 test and thus initiates the recording of the ‘remainder of
plication is assigned to the same assignee as the present
the necesary items of information pertaining to this toll
application. In general, the timing mechanism disclosed
call.
therein comprises an electric clock motor 360 for driving
More speci?cally, the operation of the third super
a mechanical cam arrangement through an intervening
visory relay 2SKT closes a plurality of contacts 2SRT1,
clutch 230 so that the cam arrangement is adapted to 50
ZSRTZ, and 2SRT4 and opens the contacts ZSRTS. The
close a pair of contacts 231 to provide a control pulse or
contacts ZSRTS and 2SRT4 form a make-before-break
signal at the end of a relatively short interval of time,
contact arrangement so that the closure of the contacts
such as an interval of from one to two seconds, during
2'SRT4 completes a holding circuit extending to the closed
which a busy test is performed by the trunk circuit to
and grounded contacts 2RD2 prior to the opening of the
determine the idle or busy condition of the line extending 55
contacts
2SRT3 to interrupt the above described operat
to the called subscriber B. The timing mechanism also
ing circuit for'the ‘relay 2SRT. The closure of the con
includes a pair of normally open contacts 232 which are
tacts 2SRT2 provides an alternative path for energizing
initially closed to provide a ?rst duration impulse approx
the
timer clutch 230 which is shunted around the con
imately sixty-?ve to sixty-seven seconds following the ener
tacts 2SR‘S1 so that, in the event that the connection is
gization ‘of the clutch 230 and which thereafter are oper
released or the line is ?ashed to intermittently operate
ated to provide duration impulses at one minute inter
and release the relays 38R and SS-RS, the timer clutch
vals, thereby to provide a means for recording informa
230 cannot be released to res-tore the timer to a normal
tion pertaining to the length of the toll call. This mecha
condition. In this manner, the timing of the call is con
nism is such that, in response to termination of the energi
tinuously maintained following the expiration of the one
zation of the timer clutch 230, the cam mechanism is im 65 to two second interval provided prior to the closure of
mediately returned to its normal starting position so that,
the contacts‘ 231 and the consequent operation of the
upon reenergization of the clutch 230, the contacts 231
third supervisory relay ZSRT.
and 232 are again closed in the sequence described above.
To initiate the recording of the next date and time
' Therefore, when the timer clutch 230 is energized by
item of information in the trunk recorder 500, the closure
the closure of the contacts ZSRSI in response to operat 70 of the contacts 2SRT1 completes an operating circuit for
ing the second supervisory relay 3SRS, the timing mecha—
a pickup relay 2PU extending through a plurality of closed
nism is placed in operation so that, after an interval of
contacts ZPUZ, 2IC3, 2CC1, and 2SRT1 to the clock
calendar circuit 220. As described in detail in the above
beween one to two seconds, the contacts 231 are closed.
identi?ed copending Clement et a1. application, the clock
However, if, as assumed above, a sixty cycle busy ?ash
ing signal, is being receivedrby the trunk circuit, the super 75 calendar circuit 220 supplies ground over the above..d@~
for the shunt relay SSH so that further operation of the
second mark pulse relay SMKS incident to recording
21
3,051,789"
.22
scribed circuit to operate the pickup relay ZPU, if the
transmission of the necessary information by the clock
clock-calendar circuit 226 is idle at the time that the con
calendar circuit 220 and in the manner described in de
tail in the above identified copending Clement et al. ap
tacts ZSRTl are closed. The operation of the pickup relay
ZPU closes a plurality of contacts 2PU1, 2PU3, ZPUS,
2PU'7, ZPUS, and SPUl and opens a plurality of contacts
2PU2, 2PU4, and 2PU6. The contacts ZPUl and ZPUZ
form a make-before-break contact arrangement so that
the closure of the contacts ZPUI completes a holding cir
plication, ground is removed from the conductor extending
to the holding contacts ZPUI of the pickup relay ZPU so
that this relay releases to open the contacts 2PU1, 2PU3,
ZPUS, 2PU7, 2PU8, and SPUl and to close the contacts
2PU2, 2PU4, and 2PU6. The opening of the contacts
ZPUS and 2PU7 and the closure of the contacts 2PU4 and
cuit for the pickup relay ZPU extending to the clock-cal
endar circuit 229 prior to the opening of the contacts 10 2PU6 interrupt the pulsing paths for the mark and space
ZPUZ to interrupt the above described operating circuit
pulse relays 3MK and 28? previously extended to the
for this relay. The opening of the contacts 2PU4- inter
clock-calendar circuit 220 and initiate the preparation of
rupts an additional point in the above described pulsing
additional circuits extending to these relays. The opening
path for the mark relay 3MK, and the concurrent closure
of the contacts 2PU1 and the closure of the contacts ZPUZ
of the contacts ZPUS connects the operating winding of the 15 interrupt the holding circuit for the pickup relay ZPU and
mark relay SMK to the clock-calendar circuit 22%) so that
reestablish the above described operating circuit for this
the mark relay 3MK is now controlled by ground pulses
relay, the operating circuit, however, being maintained
provided by the clock-calendar circuit 221}- in accordance
interrupted at the open contacts 2CC1. The opening of
with date and time information. The opening of the con
the contacts 2PU3 removes start ground from the clock
tacts 2PU6 interrupts the above described pulsing path
calendar circuit 22%, ‘and the opening of the contacts 2PU8~
for the space relay 28?, and the concurrent closure of the
contacts ZPU7 connects the operating winding of this
relay to the clock-calendar circuit 220 so that the space
relay 28F and the second space relay ESP'S are conditioned
removes the source of holding ground from the release
However, the opening of the contacts 5PU1 removes
the ground shunt around the right hand operating wind
for operation in accordance with pulses supplied by the
25 ing of the two step clock-calendar relay 5CC so that this
circuit 229.
The closure of the contacts ZPUS provides an addi
tional source of holding ground for the release delay re
lay 2RD to maintain this relay operated and, accordingly,
delay relay 2RD.
relay now fully operates to close a plurality of contacts
2CC2, SCCI, and *SCCZ. The closure of the contacts
ZCCZ reestablishes the holding ground source for the re
lease delay relay ZRD to maintain this relay operated in
the trunk circuit in an operative condition in the event 30 the event that the connection has previously been released,
that the connection is released during the interval that the
this relay normally being held operated by the closed con
clock-calendar circuit 22%;‘ provides information to the
tacts ZCBZ. The closure of the contact 3CCE provides
trunk recorder 5%. As set forth above, following the
marking ground on a conductor individual to the trunk
completion of the timing of the interval determined by the
circuit which extends to the banks of contacts of the
contacts 231, the call is to be assessed to a subscriber, and, 35 switching devices associated with the identi?er sender,
accordingly, additional holding ground means are pro
such as the identi?er sender 310, thereby to mark this
vided for maintaining the trunk circuit in an operative con
trunk circuit as requiring the association of an identi?er
dition to permit the recording of complete information
sender. The closure of the contacts 3CC2 extends start
ground to a terminal 311 which is connected to an identi
pertaining to the toll call even though the connection is
released by the subscriber.
40 ?er sender allotter (not shown) which preferably is of the
type disclosed in the above identi?ed copending Clement
The closure of the contacts SPUl completes a prelim
et al. application. The application of start ground to the
inary operating circuit for a clock-calendar relay SCC
identi?er sender allotter causes the allotter to actuate the
of the two step type so that this relay operates to close
switch in a preselected idler identi?er sender, such as the
a pair of preliminary make contacts 5CC1 and to open a
pair of preliminary break type contacts ZCCT. The clos 45 sender ‘31%, to search for and seize the contact multiples
individual to the calling trunk circuit. Accordingly, in
ure of the contacts SCCT prepares a full operating circuit
response to the completion of the transmission of date and
for the relay SCC, but this relay does not completely op
time information, as signi?ed by the release of the pickup
erate until the ground shunt around the right hand oper
relay ZPU and the consequent full operation of the clock
ating ‘winding thereof is removed by the opening of the
contacts SPUl. The opening of the contacts ZCCl pre 50 calendar relay SCC, an automatic calling line identi?ca
tion operation is initiated.
vents reoperation of the pickup relay ZPU following the
To initiate the automatic calling line identi?cation oper
completion of the transmission of the date and time infor
ation and as described in detail in the above identi?ed
mation from the clock-calendar circuit 226 to the trunk
copending Clement et al. application, the switching
recorder 50%.
Referring to the above described operation of the pickup 55 means indicated schematically in conjunction with the
relay ZPU, the closure of the contacts 2PU3 applies ground
to the clock-calendar circuit 228 to initiate a cycle of op
block diagram of the identi?er sender 310 is placed in
operation so that a plurality of wipers 316a, 310b, 3100,
and 314M step over their associated contact banks with
eration thereof during which a plurality of groups of
the wiper 310a searching for the marking ground provid
mark pulses representing instant date and time are trans
mitted over the above described circuit to the operating 60 ed at the closed contacts ‘3CC1. When the wiper 310a
moves into engagement with the contacts grounded by
winding of the mark relay 3MK, thereby to cause the
the closed contacts 3CC1, in which position the other wip
recording of this information in the recorder 55%. The
ers 310b, 310a, and 310d likewise engage contact multiples
clock-calendar circuit 229 also provides a plurality of
individual to this trunk circuit, the identi?er sender 310
ground pulses for operating the space relay 2SP to record
space pulses on the magnetic tape between adjacent groups 65 forwards ground over the wiper 3190' to complete an
obvious operating circuit for a start identi?cation relay
of the mark pulses, as described above in conjunction with
38D.
the recording of the dialed digits representing the desig
The operation of the relay BSD closes a plurality of
nation of the called substation B. When all of the neces
sary items of information pertaining to date and time
contacts ZSDl, 2SD3, 2SD4, ‘38132, 3SD3, 35134, 3SD6,
have been transmitted from the clock-calendar circuit 220, 70 and 3SD7 and opens a plurality of contacts ZSDZ, 3SD1,
the pickup relay ZPU is released to cause the full operation
and SSDS. The contacts 3SD4 and 3SD5 form a make
of the clock-calendar relay SCC as an indication that all
before-break contact arrangement so that the closure of
of the date and time information has been transmitted to
the contacts ISSDS completes a holding circuit for the
the trunk recorder 500.
relay 35D extending to the closed and grounded contacts
More speci?cally, in response to the completion of the 75 3CC1 prior to the opening of the contacts ‘3SD4 to inter
3,051,789
23
24
rupt the above described operating circuit for the relay
38D. The opening of the contacts 3SD1 interrupts the
above described operating circuits for the mark relay
in the tenth position on a terminal per station multiparty
3MK, and the concurrent closure of the contacts 3SD‘2
prepares an operating circuit for this relay extending over
the wiper 31012 to the identi?er sender 310 to condition
rices is energized to provide digital information represent
line, is connected to the plurality of party matrices 610,
‘620, and 630 so that each of these individual party mat
ing the directory numbers of all of the substations on the
line terminating in the line circuit 160. However, the out
put of only the party ten matrix ‘630 is cut through to the
input of the identi?er circuit 690, as described above, so
the mark relay 3MK for subsequent operation by ground
pulses applied to the wiper 31% from the identi?er sender,
that these signals selectively operate the identi?er circuit
310. The opening of the contacts 2SD2 interrupts the
above described operating circuits for the space relay ESP, 10 6% in accordance with the four digits forming the direc
tory number of the calling substation A. The output of
and the concurrent closure of the contacts 2SD3 inter
the identi?er circuit 690 is extended over a cable 691 to
connects the Winding of this relay with the wiper 313d
the input of the identi?er sender 310 so that digit register
to permit operation of the space relay ZSP in accordance
ing components in the sender 319 are operated in accord
with ground pulses applied to the wiper 310d by the identi
?er sender ‘310. The closure of the contacts 2SD1 pro
vides an alternative path shunted around the closed con
tacts 2IC1 for supplying holding ground to the operated
ones of the partly, digit register relays ZON, 2T0, ZTR,
15 ance with the values of the four digits forming the direc
tory number of the calling substation A,
Referring back to the preceding operation of the start
identi?cation relay ‘38D, the closure of the contacts \3SD3
completes an operating circuit for an identi?cation com
and ZSTT. The closure of the contacts 3SD7 prepares
an operating circuit for the no-identi?cation relay 3N1. 20 plete relay 31C extending from the closed and grounded
contacts 3RDS4. Operation of the identi?cation complete
The closure of the contacts 2SD4 provides an additional
source of holding ground for the release delay relay 2RD
relay 31C opens a plurality of contacts 2IC1, 2103, 2IC5,
and 5IC1 and closes a plurality of contacts 2102, 2101,
to maintain this relay operated in the event that the
‘and SICI. The closure of the contacts 3IC1 completes
connection is released during the recording of calling line
identi?cation information.
25 an obvious holding circuit for the slow-to-release identi?
cation complete relay 3IC. The closure of the contacts
The closure of the contacts 3SD6 completes an obvious
2IC2 prepares an operating circuit for the space relay
operating circuit for an identify relay 31D extending to
281’. The opening of the contacts 2IC1 interrupts the
the ground provided on the wiper 310a so that this relay
above described holding circuit for the operated party digit
operates to close the plurality of contacts ZlDl, 2ID2,
2ID3, and 3ID1. The closure of the contacts '3ID1 pro 30 register relays 2T0, 2TR, and ZSTT, but this holding cir
‘cuit is maintained through the closed contacts 2SD1.
vides an additional source of holding ground for the start
The opening of the contacts 2IC5 interrupts, at an addi
identi?cation relay 38D and for extension over the wiper
tional point, the above described operating circuit for the
310a to the identi?er sender 310.
The operation of the identify relay 31D supplies the
mark relay 3MK, and the concurrent closure of the con
identi?cation potential for return over the HS lead of 35 tacts 2IC4 prepares a path for operating the mark relay
' 3MK under the control of the timer contacts 232. The
the extended switch train to selectively energize the identi
opening of the contacts 2IC3 interrupts, at an additional
?cation matrix circuit 680 and also completes the paths
prepared by the selective operation of the party digit
register relays 2T0, ZTR, and ZSTT for operating the
point, the operating circuit for the pickup relay ZPU,
thereby to prevent reoperation of this relay.
The opening of the contacts 5IC1 interrupts the above
party matrix switching circuit 6% in accordance with the 40
stored value of the dialed party digit. More speci?cally,
described operating circuit for the clock-calendar relay
the closure of the contacts 2ID2 completes the path vex
SCC, thereby to release this relay to close the contacts
tending through the previously closed contacts 2TR4~ and
ZCCl and to open the contacts 2CC2, 3CC1, 3CC2, and
2TO6 to extend grounded battery to the “5 or '10” con
5CC1. The opening of the contacts 5CC1 interrupts, at an
ductor in the party matrix switching circuit 609. The clo 45. additional point, the operating circuit for the clock-calen
sure of the contacts 2ID1 extends ground through the
dar relay SCC. The closure of the contacts ZCCl pre
closed contacts 2STT4 to complete the operating circuit
pares a portion of the operating circuit for the pickup
for the above ?ve relay GAF so that this relay operates
relay 2PU, which circuit is interrupted at the open con
tacts 2IC3. The opening of the contacts ZCCZ removes
to close a plurality of contacts 6AF1, 6AF2, 6AF3, 6AF4,
and 6AF5. The closure of the contacts 6AF5 extends the 50 a source of holding ground for the release delay relay
grounded battery provided on the “5 or' 10” conductor
2RD, but this relay is maintained operated by the ground
to the conductor connected to the operating winding of a
provided at the closed contacts ZCBZ and 2SD4. Since
cut-through relay 61% associated with the party ten matrix
the identi?cation complete relay 31C is operated and the
630 in accordance with the above described position of the
clock-calendar relay SCC released in response to the com
calling substation A on the terminal per station multi 55 pletion of the association of the identi?er sender 310 with
party line. The operation of the relay 610 interconnects
the trunk circuit, the opening of the contacts 3CC2 re
the party ten matrix 630 with the plurality of common
moves start ground from the terminal 311 which is con
busses extending to the input of the identi?er circuit 690,
nected to the identi?er sender allotter, thereby to restore
thereby to prepare the identi?er circuit 690 for receiving
the allotter to a normal condition. Further, the opening
digital information representing the directory‘number of
of the contacts 3CC1 removes marking ground from the
the tenth party on the terminal per station multiparty line.
wiper [310a and holding ground from the relay 3SD, but
If the registered party dial is assumed to be “5” rather
the closed contacts 3ID1 maintain ground on these cir
than “10,” the relay ZSTT remains released so that the
cuits.
closure of the contacts ZlDl' operates the one-to-?ve relay
As described above, in response to the operation of the
OTF to close a plurality of contacts 6OTF1-6OTF5 so
that a party ?ve matrix switch relay (not shown) is
operated.
The closure of the contacts 2ID3 extends an identi?ca
tion potential from the power supply circuit 210 over the
HS leadtof the extended switch train through the selector
134 and the ?nder M2 to the HS multiple of the calling
line circuit 1%, thereby permitting this potential to be
extended over the identi?cation conductor 110 to the ter
minal 111.
The terminal 111, in accordance with the
identify relay 31D, the party matrix switching circuit 600
is selectively operated in accordance with the paths pre
pared by the selective operation of the operated party digit
register relays 2T0, ZTR, and ZSTT to render the party
ten matrix 630 effective to supply signals to the identi?er
circuit 6%’. The operation of the identify relay 31D fur
ther extends the identi?cation potential over the HS lead
to, the extended switch train to the terminal 111 which is
assumed to be connected in the party ten matrix 6336,
thereby to energize the input of the identi?er circuit 690
above assumption that the calling substation A is located 75 in accordance with signals representing the digits form
3,051,789’
25
ing the directory number of the calling substation A on a
terminal per station multiparty line. These signals are
conducted over the output cable 691 to the identi?er
sender 310 to store these digits in the identi?er sender 310.
In the event that an adequate calling line identi?cation is
provided in the identi?er sender 310, the sender 310 sig
nals the trunk circuit that the transmission of the stored
digits to the trunk recorder 59% may proceed. Alter
natively, in the event that satisfactory identi?cation in
formation relating to the calling substation A has not been
received by the sender 310, a signal is supplied to the
trunk circuit representing a failure in the identi?cation
process, which failure forcibly releases the connection and
prevents the recording of additional items of information
pertaining to the toll call. This latter operation is desir
able inasmuch as the failure of the automatic calling line
identi?cation means prevents the proper assessment of the
toll charge for the call.
Assuming that adequate calling line identi?cation in
26
extending to the operating winding of the relay 670, there
by releasing this cut-through relay for the party ten
matrix ‘630 and thus effectively disconnecting this matrix
from the input of the identi?er circuit 690. The opening
of the contacts 21133 removes the identi?cation potential
from the HS lead of the extended switch train and from
the energized party matrices, such as the matrices 610,
620, and 630. Accordingly, in response to the release of
the identify relay 3113, the identi?cation matrix circuit 680
and the party matrix switching circuit 600 together with
the identi?er circuit 693 are effectively released for use
in conjunction with the identi?cation of other calling sub
stations.
Incident to the removal of ground from the Wiper 3100
and the consequent release of the identify relay 31D, the
identi?er sender 310‘ initiates the transmission of four
groups of mark pulses separated by space pulses to the
mark pulse relay 3MK and the space pulse relay ZSP
for intermittently operating these relays in conjunction
formation has not been received from the identi?er circuit 20 with the second mark relay SMKS and the second space
relay 3SPS to record groups of mark pulses separated by
6% and stored in the identi?er sender 31%, the sender 310
space pulses on the magnetic tape of the trunk recorder
operates, as described in detail in the above identi?ed co
500 in accordance with the values of the digits forming the
pending Clement et al. application and Harris application,
directory number or designation of the calling substation
to apply ground to the upper operating winding of a no
identi?cation relay 3N1 through the closed contacts 3SD7 25 A. In this manner, the trunk recorder 500 is automati
cally provided with digits forming the directory number of
to operate this relay to close a plurality of contacts 3NI1
the calling substation in the event that the identi?er sender
and 3NI3 and to open a pair of contacts 3NI2. The clo
31th is provided with adequate identi?cation information
sure of the contacts 3NI3 completes a holding circuit ex
by the identi?er circuit 690.
tending to the lower winding of the relay 3N1 from the
Following the completion of the transmission of this
closed and grounded contacts 3RDS4. The closure of the 30
digital information from the identi?er sender 316 to the
contacts 3NI1 interconnects a terminal 331 with the tip
trunk recorder 5%, resistance ground is removed from the
conductor of the extended switch train through a cou
wiper 310a to release the start identi?cation relay 38D.
pling condenser, the terminal 331 being connected to a
In releasing, this relay opens the contacts ZSDi, ZSDB,
source of busy tone to provide an audible indication to the
subscriber at the calling substation A that the connection 35 28134, SSDZ, BSD-3, 3SD4, 38136, and 3SD7 and closes the
contacts ZSDZ, 38131, and 3SD5. The operations of the
cannot be completed. The opening of the contacts 3N2’.
contacts 3SD4, 3SD5, and 3SD6 prepare the above de
opens up the outgoing loop circuit from the trunk circuit,
scribed operating circuits for the start identi?cation relay
thereby to prevent the extension of the connection to the
BSD and the identify relay 31D. The opening of the con
called subscriber B. In response to the receipt of busy
tone, the connection is released by the calling subscriber 40 tacts 3SD7 interrupts the above described operating cir
cuit for the no-identi?cation relay 3N1. The opening of
at the substation A to release the calling bridge relay 3GB
the contacts SSDZ interrupts the above described operat
and restore the remainder of the operated components in
ing circuit for the mark relay SMK, and the concurrent
the trunk circuit to a normal condition. Incident to these
closure of the contacts 3SD1 interconnects the operating
releasing operations and as described in detail hereinafter,
the end-of-call relay ZEC records an end-of-call code com 45 winding of the mark relay 3MK with the prepared pulsing
path extending to the contacts 232 controlled by the trunk
prising simultaneous mark and space pulses on the mag
timing mechanism. The opening of the contacts 3SD3‘
interrupts the above described operating circuit for the
stepping switch DC, the end-of-call relay ZEC, and the
identi?cation complete relay ‘31C, but this relay remains
pulse assist relay 2PA cooperate to advance the magnetic
tape in the trunk recorder 500 a predetermined number 50 operated over the holding circuit completed at the con
tacts ‘3IC1. The opening of the contacts 2SD3 interrupts
of steps controlled by the stepping switch DC.
the above described circuit extending to the identi?er
However, assuming that adequate calling line identi?ca
sender 319 for operating the space relay ZSP, and the con
tion information is received by the identi?er sender and,
netic tape of the trunk recorder 5th), and thereafter the
in response to the storage thereof as described in detail
current closure of the contacts 2SD2 prepares another
The opening of the contacts '3ID1 removes the source
but produces no other useful function at this time.
The trunk circuit is now in condition to record duration
information in the trunk recorder 500 under the control
in the above identi?ed copending Clement et al. applica 55 operating path for the space relay 2SP. The opening of
the contacts ZSDd removes the source of holding ground
tion or in the above identi?ed copending Harris applica
for the release delay relay 2RD, but this relay is main
tion, the identi?er sender 31% supplies resistance ground to
tained operated by the closed contacts ZCBZ.
the wiper 3149a which is suf?cient to maintain the start
The opening of the contacts 2SD1 interrupts the above
identi?cation relay 38D operated but which is not suffi
cient to act as marking ground on the contact multiple in 60 described holding circuit for the operated party digit reg
ister relays 2T0, ZTR, and ZSTT so that these relays re
dividual to the trunk circuit with which the wiper 319a
lease to restore the contacts controlled thereby to a normal
is in engagement. Further, the identi?er sender 310 re
condition. The restoration of the contacts controlled by
moves ground from the wiper 310C to open the operating
these relays to their normal condition aids in conditioning
circuit for the identify relay 311) so that this relay releases
65 the trunk circuit for another cycle of recording operation,
to open the contacts ZiDl, 2iD2, ZIDS, and 3ID1.
of direct holding ground for the start identi?cation relay
3SD, but this relay remains operated over the resistance
ground provided on the Wiper 310a by the identi?er sender
of the timing mechanism individual to this trunk circuit.
310. The opening of the contacts 2ID1 removes grounded 70 The release of the start identi?cation relay 35D, in closing
the contacts 3SD1, prepares a path extending through the
battery from the operating winding of the above ?ve
closed contacts 2PU4 and 210% to a pair of contacts 232
relay 6AF, thereby releasing this relay to open the con
controlled by the timing mechanism. As designated
tacts 6AF1 to 6AF5, inclusive. The opening of the con
above, the contacts 232 are ?rst closed after an interval of
tacts 2ID2 removes grounded battery from the path pre
pared by the selective operation of the relays 2T0 and ZTR 75 approximately sixty-?ve to sixty-seven seconds following
3,051,789
27
the energization of the timer clutch 230 in response to the
the tool call. The sequential operation of these relays
receipt of answering supervisory signals from the remote
further energizes the drive magnet 530 to condition the
drive mechanism for advancing the magnetic tape a single
step.
In opening the contacts 2RD2 in response to the release
of the release delay relay 2RD, the source of main hold
ing ground is removed from the trunk circuit so that the
‘relays 2PT, 2LD, 38R, SSRS, and 2SRT release to restore
switching equipment 300. It will be noted that this inter
val is ?ve to seven seconds longer than the desired one
minute interval at which pulses are to be recorded in the
trunk recorder 50% as a representation of the duration of
the toll call.
However, this additional time interval is
added to the ?rst minute to be recorded in trunk recorder
their contacts to a normal condition. The release of these
509 to allow for the disconnect time of the switch train in
response to the release of the connection at the termina 10 relays performs no useful function at this time other than
in conditioning the trunk circuit for a cycle of operation
tion of the toll call. If this interval allowed for discon
nect time were not provided, it would be possible for a
as described ‘above. The opening of the contacts 3RD2,
subscriber to go on-hook at a time substantially at the end
2SRT2, and 2SRS1 terminates operation of the timer to
of a metered one minute interval, and the disconnect time
prevent the recording of additional duration information
of the extended switch train would be such as to permit 15 in the trunk recorder 500.
'
the recording of an additional one minute duration im
In addition to removing the source of main holding
pulse in the trunk recorder 500, thereby to cause a toll
ground from the trunk circuit, the opening of the con
charge to be assessed for an additional minute of con
tacts 2RD2 interrupts the operating circuit for the slow
versation time. By the provision of a ?rst pulse represent
to-release release delay slave relay ZRDS. This relay,
ing duration information which is transmitted a time in
20 after a suitable time interval, releases to ‘close the con
terval following a sixty second interval which is approxi
mately equal to the greatest disconnect time of the switch
tacts ZRDSI, 3RDS1, 3RDS2, and 3RDS3 and to open
the contacts 2RDS2 and 3RDS4. The closure of the
train, this improper assessment of an additional one min
contacts ZRDS! prepares an operating circuit for the
ute interval to the subscriber is prevented.
pulse assist relay 213A and one operating Winding of the
Accordingly, after an interval of between sixty-?ve to 25 differential end-ofecall relay 2EC, which path includes
sixty-sevent seconds following the receipt of answer super
the closed contacts ZRDTI and 2PB1 and extends to the
vision, the contacts 232 close to extend ground over the
home position contacts in the bank of contacts associated
circuit including the closed contacts 21(34, 2PU4, and
with the wiper 2DC4 of the stepping switch DC. The
38131 to operate the mark relay 3MK and then the sec
opening of the contacts 2RDS2 interrupts the above
ond mark relay SMKS so that a mark pulse is recorded 30 described operating circuit for the space relay 2SP ‘so
on the magnetic tape in the trunk recorder 500, and the
that this relay and the second space relay 3SPS release
drive magnet 630 is operated to condition the magnetic
to deenergize the drive magnet 530, thereby to advance
tape for being advanced a single step. Upon release
the magnetic tape in the trunk recorder 500 a single step
of the contacts 232, the mark relays 3MK and SMKS
following the recording of the space pulse disposed after
sequentially release to release the drive magnet 530‘ so 35 the group of mark pulses representing the duration in
that the magnetic tape is advanced a single step following
formation. The ‘closure of the contacts 3RDS2 reapplies
.the recording of the first mark pulse. Thereafter, the
ground to the sleeve terminal of the trunk circuit extend
contacts 232 close at sixty second intervals so that a
ing from either of the closed contacts 3RDT1 or 3DC2.
mark pulse is recorded in the trunk recorder 590 at the
The reapplication of ground to the sleeve lead at this
end of each one minute interval, thereby to provide a 40 time cannot hold the switch train extended to the trunk
number of mark pulses on the magnetic tape correspond
circuit inasmuch as the switch train has released in the
ing to the number of one minute intervals that the toll
slow-to-release interval of the release delay slave relay
connection was maintained.
ZRDS following the opening of the contacts 3RD1
The recording operations of the trunk recorder are
described above. However, the reapplication of ground
terminated in response to the release of the extended toll 45 to the sleeve terminal of the trunk circuit at this time
connection, and, incident to the release of the trunk cir
prevents the seizure of the trunk circuit for use in record
cuit, an end-of-call ‘code comprising simultaneous mark
ing items of information pertaining to a subsequent toll
and space pulses is recorded on the magnetic tape to in
call until' such time as the trunk circuit has been fully
dicate the end of the items of information pertaining to
restored to its normal condition, the end-of-call code has
the toll call. The magnetic tape is then advanced a
been recorded in the trunk recorder 500, and the magnetic
counted number of steps under the control of the pulse
tape therein advanced to a position conditioned to receive
assist relay ZPA, the end-of-call relay 2EC, and the
these next items to be recorded. The closure of the con
stepping swich DC to provide a ?xed ‘or predetermined
tacts 3RDS1 again connects the resistor 351 ‘and the con
space separating the items of information pertaining to
denser 352 across the repeat coil 320 to provide a termina
the toll call fromthe items of information to be recorded 55 tion for the trunk circuit.
pertaining to a succeeding toll call. More .speci?cally,
The closure of the contacts 3RDS3 completes an operat
when the calling substation A goes “on-hook,” the calling
ing circuit for the release or reset magnet 3DCZ of the
bridge relay 3GB is released to restore the contacts con
stepping switch DC which extends through the closed
trolled thereby to their normal position, in which position
contacts 3EC4 and the closed off-normal contacts 3DC1.
the contacts 2CB2 are opened to interrupt the operating
In response to energization of the magnet 3DCZ, the con
circuit for the slow-to-release release delay relay 2RD.
tacts 4DCZ1 are closed to provide a delayed alarm signal,
After a suitable time delay determined by the slow-to
as described above, and the plurality of wipers 2DC1,
release characteristic of the release delay relay 2RD,
2DC2, ‘2DC3, and 21303 are mechanically restored to
their‘ normal home position. In restoring the wipers to
this relay releases to restore the contacts controlled there
by to their normal position. The opening of the contacts
65 their normal position, the contacts 3DC1 and 3DC2 are
3RD1 removes ground from‘ the sleeve lead of the eX
tended switch train to permit the switch ~train extended
opened. The opening of the contacts 3DC2 removes
one source of ground from the sleeve lead of the trunk
to the trunk circuit to restore to‘ its normal condition.
The closure of the contacts 2RD} completes an operating
circuit, but ground is maintained thereon by the closed
circuit for the space relay 2SP extending through the
contacts SRDTI. The opening of the contacts 3DC1
interrupts the above described operating circuit for the
closed contacts 2RDS2 and 2IC2 so that the space relay
release magnet 3DCZ so that this relay releases to open
28F and the second space relay 3SPS are‘sequentially'
operated to energize the space pulse head 540 for record
the contacts 4-DCZ1.
‘
The restoration of the wipers of the stepping switch
ing a space pulse on the magnetic tape immediately ‘follow
-DC to their normal position conditions this stepping
ing the group of mark pulses representing the duration of 75 switch for reuse in counting intermittent operations of
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