close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2135822

код для вставки
Nov. 8, 1938.
2,135,822
C. E. LOMAX
ì
TELEPHONE SYSTEM
Filed Dec. 6, 1937
9 Sheets-Sheet 1
_.
Bom
.|__MHQkDEäÉtmÜNeá,
@E.miœnvmo.
_
n
ÉNäEzòwä?œum«„.2-z3a:
n.E uwPmvbS-O_iUEZumn-.U
_N\v3|
.GIN
__mmz3
_«ltâms\
glm231I.l
/wzäz
_l\Em,_.k
_¿cm2oz:5<r|_u0x9m2
@».dwri.
INVENTOR,
CLARENCE E. LOMAX
VM
Mm
Nov. 8, 1938'.
c, E, LolMAx
2,135,822
TELEPHONE SYSTEM
Filed Dec. 6, 1937
9 Sheets-Sheet 2
Nov. 8, 1938.
c, E. LoMAx
2,135,822
TELEPHONE SYSTEM
I
Filed-Dec. e, 1937
Q'SnQetS-sneet s
»
INVENTQR.
CLARENCE E. I_OMAX
BYS
"1a.
l l _
ATTORNEYS.
Nov. 8, 1938.-
c. E. LoMAx
2,135,822
TELEPHONE SYSTEM
Filed Dec. 6, 1957
OO.
9 Sheets-Sheet 4
Nov. 8, 1938.
I
c. E. LoMAx
2,135,822
TELEPHONE SYSTEM
Filed Dec. e, 1937
9 sheets-sheet 5
INVENTOR.
CLARENCE E. LOMAX
BYM'Z.
ATTORNEYS .
Nov. 8, 1938.
c. E. LoMAx
2,135,822l
TELEPHONE SYSTEM
Filed Dec. 6, 1937
9 Sheets-Sheetl 6
Nov. 8, 1938.
c. E. LoMAx
2,135,822
TELEPHONE SYSTEM
Filed Dec. e, 1937
9’ sheets-sheet 'I ‘
.Ewmwu
im@ß
.@S$5V1
QONQ
INVENTOIL
CLARENCE E. LOMAX
BY/@m'ó/«Áäúy
ATTORNEY5.
Nov. 8, 1938.
2,135,822
c. E. LoMAx
TELEPHONE SYSTEM
Filed Dec.. 6, 1937
9 Sheets-Sheet 8
_ ePmiœë)Üm.T@lu
INVENTOR.
CLARENCE E. ` LoMAx
BY
mœm5.
Nav. 8, 1938.
2,135,822
c. E. LoMAx
TELEPHONE SYSTEM
Filed Dec. 6, 1957
ONS
9 Sheets-Sheet 9
?
mbo-Q mbo
NFO
Inl. ,
m22âC.gé§95
Ng.„
Quo.
INVENTOR.
CLARENCE E. LOMAX
BY a
'
i ~ z
MM
AnœmV..s.
2,135,822
Patented Nov. 8, 1938
UNITED sTATEs2,135,822PATENT OFFICEI
TELEPHONE- SYSTEM
Clarence E. Lomax, Oak Park, Ill.. assigner to
Associated Electric Laboratories, Inc., Chi
cago, Ill., a corporation of Delaware
Application December 6, 1937, Serial No. 178,276
37 claims. (Cl. 179-17)
tem, improved and exceedingly simple apparatus
The present invention relates to telephone sys
tems and more particularly to power, switching
and supervisory apparatus for use in small tele
for performing, in a thoroughly reliable manner,
any and all of the functions ordinarily required
phone exchanges of the automatic type. l
in a small telephone exchange.
The operatingadvantages of the automatic
telephone exchange, as contrasted with the man
ual type of exchange, are well known in the art.
Because of these advantages, the present trend
in the installation of telephone systems favors
the use of automatic equipment in any replace
10 ment
or original installation irrespective of the
size of the system. In the construction of ex
ceedingly small exchanges for use in areas of
limited population and usually designed to serve
15 one hundred subscribers’ lines or less, the prob
lem of maintaining the manufacturing and in
stallation costs below a prohibitive value with
out sacrificing reliability of operation is a very
real one. _This is particularly true in small ex
20 changes which are entirely automatic in char
acter, as contrasted with the well-known type of
remotely controlled automatic exchange, for the
reason that the auxiliary equipment included
therein, namely, the power and supervisory appa
25 ratus, must necessarily be as complete and ex
tensive as the corresponding apparatus used in
'
More specifically, it is an object of the inven- 5
tion to provide, in a. _telephone system of the
character briefly referred to above, power and
supervisory apparatus so arranged that the req
vuislte functions of the apparatus are consolidated
in a minimum number of circuit elements.
lo
The invention as described in detail herein
after is illustrated in its embodiment in a small
community automatic exchange designed to serve
a plurality of subscribers’ lines of the party
line type and a group of two-way trunk lines 15
interconnecting the community exchange with a
main or central exchange of the manual type.
Finder-connector links employing rotary switches
are used exclusively for the line switching func
tions, allotter means being provided, in accord 20
ance with well-known practice, for assigning the
links to successive calling lines in a deflnite
order. Impulse responsive means are provided
in the connector portion of each link through
the operation of which the associated connector 5
switch is caused to perform its line selecting
larger installations. In the past, little attention functions in response to impulses transmitted
has been directed to the possibilities of reducing thereto by way of a calling subscriber’s line from
a calling substation. Inconformance with the
the construction cost of the small automatic ex
use of- party lines, namely, lines having more 30'
change
through
the
expedient
of
simplifying
the
30
power and supervisory apparatus which forms- than one substation connected thereto, the power
and supervisory apparatus is arranged for selec
a necessary adjunct of the line switching appa
ratus per se.J On the contrary, it has been the
practice to adopt more or less in toto the form
35 of this apparatus as used in the larger ex
changes, only minor alterations being made
therein for the purpose of adapting the appa
ratus to the `extensive operating requirements
inherently present in the small automatic ex
change. More specifically, it has been the prior
40
practice to provide a separate and distinct unit
for each individual supervisory function; i. e.,
separate units are provided for: generating coded
ringing current for the selective energization of
45 signalling devices associated with a called line
of the party type; supervising the allotter means
conventionally provided for switch link assign
ment purposes; supervising the line lock-out and
link release apparatus usually embodied in each
50 switch link; and other purposes. As a result, the
element of cost represented by the power and
supervisory apparatus is disproportionately large
tive ringing over either side `of a called line.
Specifically, this apparatus includes a source ofv
alternating- ringing current, a plurality of ring
ing current conductors and means comprising a
rotary interrupting switch for intermittently
connecting the conductors to the source so that
each thereof has impressed thereon the voltage
of the source for coded intervals which'are dif
ferent for each of the lines,
In general, the objects as set forth above are
in part attained in accordance with the present
invention by assigning twoor more functions to
at least a portion of the elements involved in 4
generating the interrupted ringing current.
Thus, means controlled by the interrupter switch
are provided for assigning a second linkv to
search for a calling line in the event a first as
signed link fails to ñnd the said calling line; 50
means controlled by the interrupter switch are
provided forreleasing a link seized by oneof the
lines and for preventing another link from being
in prior exchanges of small size.
It is an object of the present invention, there- y l assigned to the line in the event the connector
55 fore, to provide in an automatic telephone sys
portion of the seized link is not caused to select 55
2
2,135,822
a called line within a predetermined time interval
after the link is seized; and means controlled by
the control means for the switch are provided for
causing the connector portion of a seized link to
search for an idle one of the trunk lines on a
call which is to be extended by way of one of the
trunk lines. In accordance with a further fea
ture of the invention, an improved arrangement
is provided for applying, without interference,
Eachof the lines extending to the exchange I I
terminates in a line circuit through which it is
rendered accessible to the finder portions of the y
finder-connector links included in the exchange,
and by way of which it is terminated in the
banks of the connector portions of the various
links. Thus, the line II terminates at the line
circuit 2l through which it is connected to the
bank contacts of a connector switch 22 forming
a part of the finder-connector link 22 and by way
oi' which it is rendered accessible to the finder
portion 24 of the link 23. Similarly, the line Il
telephone connected to one subscriber’s line de
terminates at the line circuit 25 and the illus
sires a connection with a telephone connected to
15 the same line. Further features of the invention trated two-way trunk interconnecting the ex
changes III and I2 terminates at the repeater 20
pertain to the arrangement for checking the con vconnected to the line circuit 281.
dition of the apparatus in the community ex
The exchange In is designed to serve only a
change from a remote point, the arrangement
small
number of subscribers’ lines. specifically
for indicating an all-trunks-busy condition on
20 a trunk call to the distant manual exchange, and nineteen, and a small group of three trunk lines
and, accordingly, all of the subscribers’ lines and
the particular arrangement of the circuit ele
trunk lines are arranged to be served by any
ments whereby the apparatus required is reduced
one of the plurality of finder-connector links
to an absolute minimum.
included therein. Obviously, the number of links
The novel features believed to be character
required for satisfactory seryice will depend upon
25
10 ringing current to a calling line in the course of
completing a desired connection on a reverting
call, i. e., a call in which a subscriber having a
istic of the invention are set forth with particu
the volume of telephone traiiic, but, taking into
larity in the appended claims. The `invention account the character of the exchange. four links
itself, however, both as to its organization and are considered adequate for reasonably good serv
method of operation, together with further ob
ice. In order to assign the links to successive
jects and advantages thereof, will best be under
calling lines in a definite order so that a link
30 stood by reference to the specification taken in
is always available for use by a calling line, ex
connection with the accompanying drawings in cepting, oi' course, those instances when all of
-which Figure 1 illustrates diagrammatically an the
are simultaneously busy, there is pro
automatic telephone system of thetype to which videdlinks
allotter
'means as indicated at 2`l. This
the present invention is applicable; Fig. 2 illus
allotter means is suitably` interconnected with
35 trates the figure layout for the remaining fig
of the links, each line circuit, and also with
ures of the drawings; Figs. 3, 4 and 5 illustrate each
the power and supervisory apparatus indicated
the details of one of the finder-connector links at 28. The power and supervisory apparatus is
incorporated in the system of Fig. 1; Fig. 6 illus
interconnected with each of the links in the
trates the allotter means and a portion of the manner indicated.
40 power and supervisory apparatus embodied in
Neglecting for the present the details of the
the system; Fig. 7 illustrates the remaining por
circuit arrangement, the system as brieñy de
tion of the power and supervisory apparatus; scribed above is in general quite similar to con
Figs. 8 and 9 illustrate a two-way repeater ter
ventional systems, the operation of which is well
minating one of the trunk lines of the system;
understood in the art. In brief, when a sub
45 and Fig. 10 illustrates the apparatus terminating
scriber, such, for example, as the subscriber at
the opposite cnd of the trunk line extending to the
telephone A, initiates a call over the line Il
the repeater illustrated in Figs. 8 and 9.
to
a
second subscriber’s telephone, such, for ex
Referring now more particularly to Fig. l of
the drawings, the system there shown comprises ample, as the telephone B, by lifting his receiver
from its hook, the line circuit 2| causes the
50 a small community exchange I0 and a manual finder-connector link previously assigned by the
exchange I2 interconnected by a group of trunk allotter means 21 to the calling line to be started 50
lines, one of which is indicated in the drawings in operation to search for and seize the calling
as terminating at a two-way repeater circuit 20 line. Assuming that the link 22 is delegated by
forming a part of the apparatus located at the
the allotter means 21 to set up the connection,
55 exchange I0. Also extending to the exchange I0 the finder portion 24 of the link operates to se
are a plurality of subscribers’ lines, two of which - lect the calling line and to connect it through
are indicated at II and I6 having connected re
to the conductors of the link line incoming to
spectively thereto the subscribers’ substations A the
connector portion of the link. When the call
and B. The subscribers’ lines may be either of ing line I I is seized and extended by way of the
the two-conductor type or of the well-known finder
switch to the associated connector switch,
grounded type employing but a single conductor, the control
equipment of the last-mentioned
or both. With the arrangement described in de
switch is ' automatically conditioned to be re
tail hereinafter, all grounded lines are equipped sponsive to the ñrst series of impulses transmit
with adapters in order to permit the desired ted from the impulsing device at the substation A.
65 switching and signalling functions to be success
In response to the dialing of the first digit at
fully carried out. Although each of the two
the
calling substation, the connector switch 22 is
lines shown is illustrated as having only one caused
to operate in a novel manner to select the
telephone substation connected thereto, it is con
templated that a plurality of substations will be group of lines including the called line Il. There
after, and in response to the dialing of the second
70 connected to each line or, in other words, that digit, the called line IBis selected from the selected
each subscriber’s line will be of the party type.
70
Each of the substations connected to the various group of lines. When the called line is selected,
the
control
apparatus
included
in
the
link
circuit
subscribers’ lines _may comprise the usual hand
set having embodied therein a dial controlled 23 functions to test the condition' of this line,
thereby to determine the busy or idle condition
75 impulsing device of conventional arrangement. thereof.
2,135,822
3
If the called line is found busy, busy-tone cur
the distant exchange I2. In this connection, it is
rent generated by a portion of the power and
noted that two sets of link line conductors are
provided in the link circuit 23, one of which is
supervisory apparatus 28 is applied to the loop
extending to the calling subscriber’s substation,
devoid of all voice frequency coupling elements,
thereby to indicate to the calling party that the
such, for example, as condensers, and is utilized in
desired connection can not immediately be com
extending a desired connection by way of one of
pleted. If, on the other hand, the called line is
idle at the time it is selected, the calling sub
scriber may proceed to dial the third and iinal
10 digit for the purpose of selecting ringing current
of the particular code which corresponds to the
called substation B connected to the line I8. At
the conclusion of this digit, the control apparatus
embodied in the link circuit 23 functions to apply
15 the selected coded ringing current to a selected
side of the line I6, thereby to energize the sig
nalling device at the substation B in accordance
with the code identifying this substation. Dur
ing the ringing operation, ring-back tone current
20 is applied to the loop extending to the calling sub
scriber’s substation to indicate to the calling
party that the desired substation is being sig
nalled. Finally a connection between the calling
and called lines is completed when the call is
25 answered at the substation B. As pointed out
with particularity hereinafter, the arrangement
of the link circuit is such that a link utilized in
setting up a desired connection is released only
when the connection is cleared out at the calling
30 substantion.
The switching apparatus located in the ex
change I0 is also utilized in setting up a connec
tion between two substations connected to the
same line, the sole function of the apparatus in
35 this regard being that of selecting and applying
ringing current to the calling line of the proper
code to signal the called party. The discharge of
this function necessitates the seizure of the call
ing line by an idle link and the operation of the
40 connector portion of the link to select the calling
line, all in the manner outlined above.
There
the trunk lines. Following the extension of the
connection to the trunk line terminating appara
tus located in the exchange I2, the connection
may further be extended to the desired called line 10
through the intervention of an operator in the
manner conventionally followed in manual ex
change operation. Following the establishment
of a connection in the above-described manner,
the release of the connection is entirely under 15
the control of the operator in the exchange I2.
Since the trunk lines interconnecting the ex
changes I0 and I2 are of the two-way type, it
follows that any one of these lines and the switch
ing apparatus included in the exchange I0 may 20
be utilized in the completion of calls originating
or extending by way of the exchange I2 and
which are to be extended to one of the subscribers’
lines terminating at the exchange I0. The mode
of operation of the equipment in the exchange I0, 25
following the extension of a call thereto by way of
one of the trunk lines noted, is exactly the same
as that set forth above with reference to the con
nection established between the substations A
and B, it being observed that each of these trunk 30
lines terminates in a line circuit identical with
that associated with each of the subscribers’ lines.
Here again the release of the connection is entire
ly under the control of the intervening operator
35
who originates the call in the exchange I2.
Considering now in greater detail the apparatus
embodied in the exchange I0 and involved in the
above-described sequence of operations, and re
ferring more particularly to the apparatus illus
trated in Figs. 3, 4 and 5, there are illustrated the 40
elements of the line circuit 2I terminating the
subscriber’s line I I, and the finder-connector link
after, and following the dialing of the ringing cur
rent code selecting digit at the calling substation, ’ 23. The line circuit comprises a line relay R3I0,
the calling party restores his receiver to its hook a cut-off relay R320, a'nd a line lock-out relay
R300, all arranged in accordance with conven
and ringing current of the selected code identify
ing the called substation is projected over the tional practice. This circuit also includes a ccn
denser 305 through which pay-station tone cur
calling line. When the call is answered, the oper
ated link is released and the line circuit of the line rent may be applied to the control conductor
in service operates to busy the line and thereby C394 of the line II from an alternating current
prevent
its seizure by the connector portion of source, not shown, for purposes referred to spe
50
cifically hereinafter. This pay-station tone cir
another link on a subsequent call. Finally the
line circuit of the line is restored to normal when cuit is shown in association with the line II for
illustrative purposes only, it being pointed out
the connection is cleared out.
In the operation of the link to select one of the that a circuit of this form is provided only in as
sociation with those of the lines terminating at
small group of trunk lines outgoing from the ex
change I0 and extending to the exchange I2, the exchange I0 having telephones of the pay
only two predetermined digits are required to station type connected thereto. Since the ap
cause the connector portion of the link to select paratus for applying pay-station tone current to
the conductor C394 may be entirely conventional
the group of trunk lines. At the conclusion of
in character, an illustration thereof is omitted.
60 these two digits and, in accordance with one fea
The line circuits respectively associated with
ture of the present invention, certain of the ele
ments embodied in the link circuit 23 cooperate each of the other lines extending to the exchange
with a portion of the equipment in the power and I0 are identical with that terminating the line
II, and, hence, that terminating the trunk line
supervisory apparatus 28 to cause the connector
|00 and indicated at 381 is only diagrammatically
65 switch 22 to operate in the manner of a trunk
hunting selector switch. Immediately the series illustrated.
The finder portion of the link 23 comprises the
of impulses comprising the second digit is con
cluded, this last-mentioned apparatus is started
into operation to cause the connector switch 22
to search for an idle one of the selected group
of trunk lines. When an idle trunk line is found,
55
.
65
stepping switch 380 and the line switching relay
R350. The switch 380 is of the standard rotary
type and comprises three sets of bank contacts 70
the trunk-hunting operation is interrupted and
384, 385, and 386, of twenty-five points each,
wipers 38|, 382 and 383 respectively associated
the calling line is extended by way of the selected
trunk line and the associated two-way repeater
with the contact sets 384, 385 and 386, and means
comprising the motor magnet M330 and a ratchet
75 circuit `to the terminating apparatus located at
50
and pawl mechanism, not shown, for driving the 76
4
2,135,822
enumerated wipers over the contacts of their re
spective associated sets. The connector portion
of the link similarly includes a rotary switch
550 of standard 'construction which comprises
bank contact sets 55|, 552, 553, 554 and 555,
Wipers 58|, 582, 583, 584 and 585 respectively
associated with the contact sets in the order of
, their enumeration, and means comprising the
motor magnet M540 and a ratchet and pawl
mechanism, not shown, for driving the wipers
over the contacts of their respective associated
contact sets. As regards the connector portion of
the link, the conductors of the lines extending to
the exchange |0 are terminated at the contacts of
the sets 55| and 552 of the switch 550 and the
private or control conductors of these lines ex
tend to the contacts of the set 553. Specifically,
the subscribers’ lines are divided into two groups
comprising ten lines and nine lines, respectively.
'I'he lines of the ten-line group are connected to
the contacts numbered from three to twelve of the
indicated contact sets while the lines of the nine
line group are connected to the contacts num
bered from fourteen to twenty-two.
The con
tacts corresponding to the twenty-third, twenty
fourth, and twenty-fifth off-normal positions of
the switch are reserved for terminating the con
ductors of the three trunk lines interconnecting
the exchange I0 with the exchange i2.
Also included in the link circuit is a ringing
current code selector switch 560. This switch,
which is of the well-known minor type, includes
two sets of bank contacts 56| and 562, wipers
563 and 564 respectively associated with the con
tact sets 56| and 562, means comprising thc motor
magnet M565 and a ratchet and pawl mecha
nism, not shown, for driving the enumerated
wipers over their respective associated contacts, a
release magnet M566 operative to restore the
switch to normal, and a set of off-normal springs
v510 for controlling certain of the relays referred
to hereinafter. The switch 560 has terminating
in its upper set of bank contacts, in the manner
indicated, five ringing current conductors C|54
45 to C|58, inclusive, which lead to the power and
supervisory apparatus illustrated in Fig. 7 by
way of the cable |50.
Although the particular arrangement of the
control relays will best be understood by refer
ence to the detailed description of the operation
which follows, it is believed that a brief reference
calling substation and is directly controlled by
R460 and R450. Testing of a called line selected
by the connector portion ot the link to determine
its idle or busy condition is achieved through the
provision of the busy relay R410, the operating
circuit for' this relay being held prepared during
second digit impulsing’ by means comprising the
relay R450. The application of ringing current
to a selected called line is an assigned function
of the ringing relay R530, this relay in turn being
controlled by the interrelated operation of R400'
and the coue selector switch 560. As pointed out
in detail hereinafter. the selection of a particular
ringing code and the proper application of ringing
current to a selected called line is tantamount 15
to the selection of one of the group of ringing
current conductors C|54 to CI50, inclusive, and
the connection of this selected conductor to
project ringing current over only one side of the
selected line, ground return ringing being utilized
throughout.
The interruption of the ringing operation when
a called substation on a selected called line an
swers
is
accomplished in ' the usual manner
through the operation of R520, which- relay will
be recognized as the conventional ring cut-off re
lay. The operation of this relay also results in
the completion of a talking loop to the called
subscriber’s substation and in the completion of
a circuit including this loop for energizing the 30
supervisory relay R400. The last-mentioned re
lay is a slave relay which controls the energiza
tion of the battery reversing relay R360. This
battery reversing relay performs the usual func
tion of reversing the polarity of the direct po
tential applied to the loop extending to a call
ing subscriber’s substation for metering or other
supervisory purposes.
In order to adapt the link circuit for efficient
ringing during the establishing of a reverting call 40
and for additional purposes pointed out herein
after, there are provided two additional relays
R430 and R350. The first of these relays is en
ergized only in the course of completing a revert
ing call and functions to control R350, which lat
ter relay is a switching relayA eiïective to switch
theline conductors of the calling line from a
connection with the set of link line conductors
C|04 and C|00 to a connection with the set of
link line conductors C|05 and C|08. 'I'he pur
pose of thus switching the conductors of a call 50
ing line to C|05 and C|09 on a reverting call is
to remove the winding of R400 from across the
to the functions performed by certain combina
tions of these relays will facilitate an under
standing of the features of the circuit to which
the present invention relates. In this connection,
it is pointed out that R310 is the usual line relay
ing current during the ringing operation.
which responds to impulses transmitted over a
calling line to the link circuit; R403 is the usual
A further function of R350 is that of switch
ing the conductors of a calling line, in the man
ringing circuit thereby to prevent this winding
from shunting a substantial portion of the ling
hold relay for holding the ñnder portion of the ner noted, in the course of completing a connec
link operated following the seizure thereof and tion extending by way of one of the trunk lines
during impulsing; R4|0 is a relay which operates »interconnecting the exchange I0 and the ex
to repeat impulses transmitted to R310; R420 is change, |2 so that the voice coupling condensers
a slave relay controlled by R403; and that these 308 and 390 are removed from the loop circuit.
four relays, in combination with the circuits con
In this case the operation of the switching relay
trolled thereby, comprise impulse responsive R350 is under the control of R500 which latter re
means for causing the connector switch 550 to
select any desired subscriber’s line or the group
of trunk lines terminating at the exchange and
for causing the code selector switch 560 to select
70 a desired ringing current conductor for connec
tion to the selected line. Transfer of the impuls
ing circuit from the magnet M540 of the switch
550 to the magnet M565 of the code selector switch
lay also enters into the trunk-hunting operation
of the rotary switch 550 during the movement
of the switch to select an idle outgoing trunk
line.
As pointed out in the introductory portion of 70
the speciiìcation, one feature of the invention is
concerned with the provision of means for lock
ing out a calling line in the event a connection
560 is a function assigned to R490, which relay ‘
operates at the end of the second digit dialed at a is not established to a desired called line within
a predetermined time interval after the seizure 1I
5
2,185,822
of one of the links. Specifically, this means com
prises. in addition to portions of the power and
supervisory apparatus illustrated in Fig. '1, the
relay R440' and the line and lockout relays, such,
for example, as the relays R320 and R300, em
bodied in the line circuit 21.
In order to adapt the link circuit illustrated-for use in connection with lines of the grounded
type, i. e., lines including a single line conductor
10 and a ground return path, there is'provided, in
addition to the apparatus already mentioned, the-l
relay R510 which functions to control certain of
the relays in the link circuit only in the event
a line of the grounded type is selected.
.
In order to remove the finder-connector link
from service for purposes of repair or testing,
15
there is included therein the manually operable
switch 395. This switch is normally maintained
in the position shown« in the drawings but, -when
operated to its off-normal position, functions in
a conventional manner to mark the link as busy
in the allotter means, thereby to prevent the link
from being assigned for use.
f
Referring now more particularly to the allotter
25 means as illustrated in Fig. 6, this means com
prises, in brief,l a rotary switch 610, a link start
relay R610, a hold relay R605, an impulsing re
lay R620, a link transfer relay R625, and an all
links-busy relay R600. The switch 610 is of the
30 standard rotary type and includes four sets of
bank contacts 616 to 618. inclusive, wipers 611
to 614 respectively associated with the bank con
tact sets in the order of their enumeration and
means comprising a ratchet and pawl mecha
nism, not shown, and a motor magnet M660 for
driving the wipers step by step over the con
. tacts of their respective associated contact sets.
As indicated above, this allotter means is >ar
ranged to control the selection of an idle link
from a group of four links, the various control
conductors being terminated in the bank con
tacts of the switch 610 in the manner illustrated.
As will be apparent from the detailed description
which follows, the mode of operation of the allot
ter means is‘more or less conventional in form
as regards its function to~ select idle ones of the
associated links. It is noted, however, that the
manner in which the link transfer relay R625
cooperates with certain of the elements embodied
in the power and supervisory apparatus, to as
sign a second link to a calling line upon failure
of a first assigned link to find the line, departs
from conventional practice and forms the sub-ject matter of one feature of the present inven-55 tion.
"The power and supervisory apparatus which
is illustrated in the lower portion of Fig. 6 and
in Fig. 'l comprises, in brief, a source of ringing
current in the form of a mechanical inverter
shown in the lower left-hand portion of Fig. 6,
60 the
five ringing current conductors C154 to C158,
inclusive, and means comprising the rotary switch
110 for intermittently connecting these conduc
tors to
65
ringing current source so. that each
thereof has impressed thereon the voltage of this
source for coded intervals which are diiïerent for
each of the conductors. The last-mentioned
means also comprises the control means for the
switch 11, which control means specifically in
c‘udes the relays R101, R110, R115 and R120.
70 Also arranged to be controlled byv the four relays
noted are the self-restoring relays R100 and R105
which comprise respectively a source of busy-tone
current and a source of dial tone current. lThe
'Il four relays forming the control means for the
switch 110 also function to control the two re
lays R650 and R655, which latter relays, in com
bination with R500 or a correspondingrelay em
bodied in another' of the links', ,comprise means
for causing the connector portion of a seized link
to select an idle trunk outgoing from the ex
change 10 on a call which is to be completed
by way of one of these trunks.“
The switch -1‘10 not only functions as a
ringing current interrupter switch but, in ad 10
dition, forms " an integral part of a 'timing
unit for applying supervisory groun pulses
to the three supervisory conductors C131,
C135 and C146. 'I'his unit includes. in addi
tion to the switch noted, the four cyclically oper 15
ating relays R124, R130, R135 and R140. 'I'he
arrangement is such that the ringing apparatus
is utilized for alarm purposes for indicating to
a supervisory substation the condition of the
equipment in the exchange 10. To this end the 20
three relays R150, R155 and R160 are embodied
in the power and supervisory apparatus, which
relays control, in accordance with the condition
of the equipment, the characteristic of the volt
age applied to the alarm conductor C152 and 25
utilized for checking the condition of the equip
‘ ment from a remote point.
,
The two-way repeater illustrated in Figs. 8 and
9 associated with one of the trunklines inter
connecting the exchanges 10 and 12 and the ap 30
paratus terminating this trunk line in the ex
change I2, as illustrated in Fig. 10, are of more
or less conventional arrangement. Since this
portion of the system is illustrated primarily for
the purpose of insuring a complete disclosure 35
with reference to the operation of the equipment
located in the exchange 10, it is thought that a
detailed consideration of the various elements
included therein is unnecessary at this point in
the description, the function of these elements 40
being pointed out with particularity in the fol
lowing description. All of the relays included
in this equipment, as well as the relays specifi
cally mentioned above, are illustrated in accord
ance with well-deñned conventions to indicate 45
the particular operating characteristics possessed
thereby.
Operation of the finder switch. to seize the call
ing line
50
Referring now more particularly to the opera
tion of the apparatus located in the rural oilice
10 to establish a connection between the lines 11
and 16 on a call from the subomce A to the sub
station B and assuming that the link illustrated
in Figs. 3 to 5, inclusive, is the link delegated by
the allotter means shown in Fig. 6 to set up the
connection, the operation of this link is initiated
when the calling party atv the substation A re- «
moves his receiver from its hook to complete the 60
usual subscriber's loop circuit for energizing the
line relay R310. The circuit noted extends from
ground at RA322 by way of the lower winding of
R310; C393, the directcurrent bridge across C393
and C392 at the substation A, C392, RA321 and 65
Ilthrough the upper winding of R310 to battery.
The relay R310 upon operating applies, at RA312
and, RC313, ground to the control conductor
C394, thereby to mark the calling. line I 1 as busy
in the bank contacts of the connector switches 70
to which this line extends. At RA315, the relay
R310 marks the calling line in the bank con
tacts of the rotary finder switch 380 by applying
battery through the cut-oil relay R320 by way of
RA304, RA315 and C393’ to the contact in the 75
6
2,135,322
contact set 000 which corresponds to the calling
a holding circuit, traced hereinafter. for
line. At_RAOII, the re1ay'ROI0 applies ground pares
the switching relay R040.
`
'
to the start conductor CI24 to start the ilnder
The
relay
R420
upon
operating
prepares,
at its
portion oi' the link in operation to search for and
armatures RA42| and RA420, Vholding circuits for '
seize the calling line.
Thus. when ground is applied to CI24, a circuit certain of the relays specifically referred to here
is completed for energizing RlIl in series with inafter. When R420 operates it also removes, at
the multiply connected motor magnets M000 and RA42I, ground from the conductor CI20 thereby
M040. In this connection it is pointed out that, to open one oi' the multiple holding circuits for
10 with any one of the several links embodied in the R000 embodied in_ the allotter. The relay R420,
oilice I0 idle, R000 is in an energized condition upon operating, further completes, at RA421, a (l
circuit for energizing the relay R120 embodied In
so that the above-noted circuit for ROIl is coin
pleted immediately upon the operation oi' the the power and supervisory apparatus illustrated
line relay ROI0 or any other line relay. This in Fig. 7, this circuit extending from ground at
RA42'I by way oi the start conductor Ci22 and `
15 circuit extends from ground on CI24 by way of
through the winding oi' R120 to battery.
RA002 and the winding of R0_Il where it divides,
When R000 operates substantially simultane
one branch extending by way o! RAO0I, MAO0I
and the winding of M000 to battery, and the ously with the operation oi' R010, it prepares at
other branch extending by way oi' RAOI2, CI00, RA000 a circuit,'traced hereinafter, for energiz
ing M000 and, at RAlll, completes an obvious
20 the switch wiper 01|, CI00, RA040, RC040, the
switch springs 000 and 001, CI2l, RA420, CIIl,
RA000. CI2I, RA400, RA40'I', RC400', Clll,
MA042 and through the winding oi.' M040 to bat
tery. Due to the resistance of the winding of
ROI0, the two magnets noted, namely, M000 and
M040, are not suiiiciently energized tó attract
their associated armatures and, hence, remain in
active. The relay ROI0, however, operates to in
terrupt. at RAOI2, a point in the above-traced
branch of the circuit described which extends to
M040. At RAOI0 the relay ROI0 prepares a cir
cuit. traced hereinafter, ior energizing R020 and,
at its amature RAOI0, it completes a circuit ex
tending by way of RCOI0 for energizing R000.
35 The operation of R0|0 also results in the ener
gization of the motor magnet M000 embodied in
the rotary switch 000 over a circuit extending
from ground at RAOI0 by way oi’ RCOI0, RA02I,
CIOI, the switch wiper 014, Ci20, RA040 and
through the winding of M000 to battery. At
RAOI'I, the relay ROI0 applies multiple ground to
CI20, thereby to maintain R000 operated inde
pendently oi' the condition of the other links em
bodied in the oñice I0. At RAOI I, the relay ROI0
45 completes a circuit for energizing the upper wind
ing of R010, this circuit extending from ground
at RAOII by way of the resistor 00|, Ci04, the
switch wiper 012, CI20 and through the upper
winding of R010 to battery.
The relay R010 operates when its upper wind
ing is energized, and completes, at RA01I. a cir
cuit for energizing R4I0, this circuit extending
from ground at RA401 by way of RC400, CIIO,
RAJ‘II, CI Ii and through the winding of R4I0 to
battery. At RA012, the relay R010 prepares a
holding circuit for R400. The operating circuit
for the last-mentioned relay is completed upon
the operation ot R4I0 and extends from ground
at RA4I2 by way of RC4I0, CIIO, and the wind
ing of R400 to battery. The relay R4I0 upon
operating also completes a holding circuit for
itself, this circuit extending i'rom ground at
RA4II by way of the resistor 440, CIIO, RAl‘H,
CIII and the Winding of R4I0 to battery.
05
'I‘he relay R403, upon operating, similarly com
multiple holding circuit for R000. At RAlll, the 20
relay Rlllextends ground through the upper
winding of R020 and the switch wiper 010 to the
test conductor CI21, thereby to provide a path
over which the upper winding of the switching
relay R040 may be energized when the wipers oi' 25
the rotary switch 000 are subsequently stepped to
a position corresponding to the calling line Il .
The magnet M000, upon being energized in re
sponse to the operation o! ROI0, attracts RAO0I
to complete a circuit extending by way of CI20 30
tor energizing the lower winding of R020. The
relay R020, in turn, operates to interrupt, at
RA02I, the above-traced circuit i'or M000. 'I'he
magnet M000 now restores to step the associated
switch wipers 00|, 002 and 000 one step and to 35
interrupt, at RAO0I, the operating circuit for
R020. The relay R020 again restores to recom
plete the operating circuit for M000. 'I'his inter
related operation of M000 and R020 continues
until such time as the wipers or the switch 000
are stepped to a position corresponding to the 40
calling line II. In the present assumed case,
wherein the control conductor C000' extends to
the third contact oi' the contact set 000, the
switch 000 is caused to take three steps from the
position shown in the drawings, at which time 45
the switch wiper 000 engages its associated third
contact to complete a circuit for energizing the
upper winding of R040. This circuit extends
from battery at the cut-oi! relay R020 by way of
RA004, RAOI0. C000', the switch wiper 000, the 50
upper winding of R040, CI21, the switch wiper
010, Ci02 and through the upper winding of
R020 to ground at RA000. Since the upper
winding oi’ R020 is now being energized over a
circuit which is independent of M000, this relay 55
stays operated to hold open the operating cir
cuit for M030. As a result. the interrelated op
eration of this relay and M000 is discontinued.
When the upper winding of R040 is energized
over the above-noted circuit, this relay partially (l04
operates to complete, at RA044, a circuit for en
ergizing its lower winding, this latter circuit ex
tending from ground at RA442 by way of RA400,
pletes, at RA401, the above-noted holding circuit
CIIO,`RA044, and the lower winding of R040 to
battery. With its lower winding energized, R040
for itself, which circuit extends from ground at
completes its operation to interrupt, at RA040, a
further point in the operating circuit for M000
RA401 by way of RC400, CIIO, RA012, RCO'I0,
70 CIIS and through the winding of R400 to bat
tery. The relay R400 further completes, at
RA405 and RA400, a circuit for energizing R420,
this circuit extending from ground at RA442 by
way of RA400, RA405, and the winding of R420
to battery. At RA400, the relay R400 also pre
and to complete, at RA040, a circuit i’or ener
gizing the cut-oil relay R020 associated with the
calling line Il. At RA040, the relay R040 corn
pletes a circuit for energizing M060, thereby to
cause the ailotter means to operate in the man
ner pointed out hereinafter to a position corre~
spending to the next idle link.
7
2,135,822
Cil
'I'he above-noted circuit for energizing the cut
oiî relay R320 extends from ground at RA442 by
way of RA406, C||0, RA344, RA345, the switch
wiperl 383, C393', RA3I5, RA304 and through the
is continued until such time as the-wiper 61| en
-counters a contact in the associated set 615 corre
winding of R320 to battery. This relay, upon
operating, short circuits, at RA326, the armatures
RA3|5 and RA304 thereby to provide a holding
circuit for itself and, at its armatures RA32| and
energizing M660, and the operation of the rotary
switch 610 is interrupted. With the switch stand
RA322, interrupts the above-traced operating
the exact manner just described with reference
to the link illustrated in Figs. 3 to 5, inclusive. 10
As was pointed out above, operation of R340,
10 circuit for the line relay R3l0.
The last-inen
tioned relay, upon restoring; removes, at RA3| I,
ground from the start conductor-CI24; opens, at
RA3|5, the marking path as traced above; and
completes, at RA3|2 and RC3I4, an alternative
15 path for applying ground to the control conduc
tor C394 from the ground extended to C393’. At
RA322, the cut-off relay, upon operating, com
sponding to an idle under-connector link. When
this occurs, no further circuit is completed for
ing in this new position, circuits are prepared for
seizing the selected idle finder-connector link in
following the operation of the link to seize the
calling line ||, is followed by operation of the
cut-olf relay R320 and the restoration'bf the line
relay R3|0. The last-mentioned relay, upon re
storing, interrupts at RA3| |, the operating circuit
for R6|0, which latter relay, upon falling back,
pletes an obvious circuit for energizing the slow- ' interrupts, at RABIS, the operating circuit for
to-release line lockout relay R300, which latter _ R605. 'I‘he relay R605, u_pon restoring, opens the
20 relay now operates to open a further point in the only remaining operating circuit for R620, causing
path for applying ground to the start conductor this relay to restore. Thus, the apparatus in
C|24 and a further point in the path for marking
the calling line in the bank contacts oi’ the rotary
cluded in the allotter means illustrated in Fig. 6
is restored to normal and is prepared for further
switch 380.
use.
,
25 ‘ Immediately upon the operation of the switch
'
As indicated previously, the seizure of any link 25
ing relay R340, the subscriber's loop incoming
is accompanied by the operation of the relay
from the calling substation A is extended by way
corresponding to R420. Each of these relays,
upon operating, functions to interrupt, at RA42|
of RA34| and RA342 to the link line conductors
C|04 and C|08. The extension of this loop to
30 these conductors results in the completion of an
alternative operating circuit for R310, which cir
cuit extends from ground at the lower winding of
this relay by way of the said lower winding,
RA364, RC356, RA355,ÃRA342, the switch wiper
and RC423, a point in the operating circuit for
R600. Hence, when all of the links are busy so
that all of the relays corresponding to and in
cluding R420 are energized, the operating circuit
for R600 is completely open and this relay rè
stores.
As a consequence, it is impossible for a
:o Ca 382, C393, the bridge across C393 and C932 at
calling line to initiate the operation of any finder
the substation A, C392, the switch wiper 38|,
RA34I, RA352, RC353, RA362 and through the
switch in search thereof. A call initiated at a
time when such a condition prevails will, there
fore, not be rewarded with dial tone and cannot be
upper winding of R310 to battery. With the sub
scriber’s loop thus extended and the relays R300,
40 R320, R340, R310, R403, R4|0 and R420 oper
ated, the connector portion of the link is condi
tioned to respond to impulses transmitted thereto
from the impulsing device conventionally pro
extended until such time as one of the links is
again idle. Obviously, when one of the links is 40
released following an all-links busy condition, the
all-links busy relay R600 is again caused to oper
ate. From the preceding description it will be
/ apparent that when all of the links are busy the
vided at the calling substation A.
Operation of the allotter means to find an idle link switch 610 continues to operate in search of an
idle link until R600 restores to cause the se
Before describing the operation of the link dur
quential restoration of R6 | 0 and R605. The last
ing the transmission of impulses thereto from mentioned relay upon restoring opens the oper
the calling subscriber's substation, the opera
ating circuit for M660 causing the switch 610 to
tion of the allotter means illustrated in Fig. `6 discontinue its hunting operation. Thereafter,
50 will be considered. In this connection, it will be
and when R600, R6|0 and R605 are again caused
noted that a busy link is identiñed by the pres
to operate, the switch 610 is started in opera
ence of ground on the guard conductor corre
tion to find the idle link responsible for the re
sponding to Cl 30 for the link illustrated, whereas, operation of R600 and to assign this link to the
calling line responsible for the operation of R6|0
55 if the link is idle, battery is present on this con
ductor. Thus, immediately u_pon the operation and R605.
of R340, ground is applied, at RA346 and RC341, Operation of the power and supervisory apparatus
to CI30, thereby to mark the associated link as
Before describing the operation of 'the oon
busy in the bank contacts oi"r the rotary switch
nector
portion of the link to select the called
610
and,
with
this
switch
standing
in
the
posi
60
line |6 in response to the transmission of im
tion corresponding to this link, a circuit is com
pleted for energizing the motor magnet M660. pulses thereto from the calling substation A, and
This circuit extends from ground at RC341 by in order to render this portion of the description
way of RA346, CI30, the switch wiper 61|, CI33, more clearly understandable, the operation of
the power and supervisory apparatus, illustrated
05 RA606, and through the winding of M660 to bat
tery. The magnet M660, upon being energized, in Fig. '1 and the lower portion of Fig. 6, will
steps its associated wipers 61| to 614, inclusive, now be considered. As pointed out previously,
this apparatus includes an invertor circuit, in
one step so that the above-traced operating cir
cuit is interrupted at the wiper 61| and the bank dicated as the ringing current source, for trans
forming the exchange battery voltage into an
70 contact terminating C|30. If the link corre
sponding to the second contact of the contact set alternating ringing voltage, a plurality of ring
-615 is busy, ground is present on this contact ing current conductors, C|54, C|55, C|56, C|51
and C|58, and a ringing interrupter comprising
and a new circuit is completed for energizing
M560, thereby to cause this magnet to step the the rotary switch 110 and the associated control
75 enumerated wipers a second step. This action means for controlling the connection of the ring
45
50
55
60
65
70
7
8
9,185,829
ing current conductors to the alternating voltage
source. 'I'he arrangement of the enumerated ele
ments is' such that each of the ringing current
conductors has impressed thereon the voltage of
the source for coded intervals which are dif
ferent for each of the various conductors. The
power'and supervisory apparatus also includes a
timing device for generating spaced supervisory
impulses which are utilized in the operation of
10 any one of the links to lockvl out a faulty line
until the fault is corrected, and are also utilized
in the operation of the allotter means to cause
different links successively to be assigned to a
callingvline in the event.the assigned links fail
to ilnd a calling line. This apparatus further
comprises means partially controlled by the ring
ing current interrupter for causing the connec
tor portion of an operated link to search for
an idle outgoing trunk line when a connection
extending by way of such a line is desired- by the
calling subscriber. An additional feature of this
apparatus pertains to the provision of circuit ele
ments arranged to form a busy-tone current
source and a dial-tone current source all _in the
manner described immediately hereinafter.
As pointed out above, the operation of the
powerand supervisory apparatus is initiated by
the operation of R126 during the sequence of
operations just described and immediately the
winding 662 and completes, at its associated con
tacts RC646 and RC646, circuits for respectively
energizing the lower winding 663 of the trans
former 666 and the previously-traced path for
short-circuiting the winding of R646. The ener
gizing circuit for the winding 663 extends from
ground at the inductance coil 666 by way of the
inductance coil 666, the winding 663, RC644,
RAMI, RCB“ and RA646' t0 battery.
Obvl- `
ously, with thewinding of R645 short~circuited,
the armature spring RAI" is again released and
is again carried by its weighted end into engage
ment with RC641 to open the above-traced cir
cuit- for energizing the transformer winding 663
and to recomplete the above-traced circuit for 15
energizing the transformer winding 662. The
amature noted, namely RA646, continues to
vibrate alternately to complete the two above
traced circuits for energizing the two transform
er windings 662 and 663.
These two windings 20'
are connected in opposition and, as a result, an
alternating voltage is induced in the secondary
winding 661, which is utilized for ringing pur
poses in the manner pointed out in detail here
inafter. Obviously, the frequency of this volt 25
age is determined by the vibrating period of the
amature spring RA646.
For the purpose of preventing arcing at the
contacts controlled by the relay R645, a sup
link illustrated 'is taken for use. Upon operating,
R126 completes a circuit for energizing R636,
pressor network is connected in shunt with the 30
units referred to above is started in operation
tion ensuing over an established connection.
to perform the respective functions assigned
thereto. Thus, the operation of the invertor
illustrated in the lower left-hand corner of Fig.
6 is initiated upon the operation of the relays
R636 and R645. The last-mentioned relay upon
From the foregoing description it will be ap
parent that ringing voltage is generated continu
ously so long as R126 is maintained energized.
This voltage is adapted to be impressed by a se
lected one of the five ringing current conductors
being energized attracts its- weighted amature
C154l C155, C156, C151 and C156, comprising the
RA646 to prepare at RC646 a path for short
cable 156, on one or both of the line conductors
of a called line selected by any one of the links
two seriesconnected windings 662 and 663. 'I‘his
R645, R655, the upper winding of R166, and the network comprises the condensers 666 and 661
upper windings of R165 and R161, respectively. >and the resistors 664 and 666 connected in series,
'I'his circuit extends from ground at RA121 to with the Junction point between the two resistors
- C166 where it divides, separate branches thereof connected to battery.` The two inductance coils
extending through the designated windings of 666 and 666 are provided for the purpose of sup
the various relays noted to battery. Through pressing, in a conventional manner, transient cur
the operation of these relays, each of the various rents which would interfere with the conversa
circuiting its own winding. ' This path is sub
sequently completed upon the operation of the
slow-to-operate relay R636 and extends from
battery at RA646 by way of RC646, RC634, RA632
and through thewinding of RA645 back to bat~
tery. 'I'he relay R636, upon operating; also com
pletes, at RA631, a circuit extending from ground
on C136 for energizing the lower winding of
R646, which latter relay operates after an inter#
- val, to open at RA642 and RC643, the path nor
mally short-circuiting its upper winding and to
prepare at RA641 a circuit for >energizing the
upper winding 662 of the transformer 666. With
R645 deenergized, due to the short-circuited con
dition of its winding, the weighted armature
RA646 is released and, upon its back stroke,
engages RC641 to complete the above-noted cir
cuit for energizing the transformer winding 662,
this circuit extending from ground at the induct
ance coil 668 by way of the inductance coil 666,
the winding 662, RA641, RC641 and RA646 to
battery. The weighted armature RA646 upon
its back stroke also interrupts the above-traced
70 path short-circuiting the winding of R645, caus
ing this winding to be energized in series with
the resistor 636, whereby R645 again attracts
RA646.
On its second forward stroke the ar
mature RA646 interrupts, at RC641,l the above
traced circuit for energizing the transformer
embodied in the office I6. The various paths for
applying the voltage developed across the second
ary windings of the transformer 666 to the five
enumerated conductors are interrupted, through
the operation of the rotary switch 116 and the
control relays R161, R116 and R115, in a manner
such that the ringing voltage as ultimately ap
plied to the conductors of a called line is coded
in a particular manner. More specifically, the
arrangement is such that coded ringing voltage
representing one long for each ringing cycle is
applied to the ringing current conductor C156;
coded ringing voltage representing two shorts for
each ringing cycle is applied to C166; coded ring
ing voltage representing three shorts is applied
during each ringing cycle to C154; coded ringing
voltage representing four shorts is applied dur
ing each ringing cycle to C151: and coded ringing
voltage representing one long and one short is
applied during each ringing cycle to C155. 'I'he
'operation of the elements noted to interrupt the
ringing voltage so that codes of the designated
characteristics are applied to the respective enu
merated ringing current conductors is initiated. 70
as was pointed out above, upon the operation of
R126 to complete a. circuit for energizing- R161.
It will be noted that with the three relays R161,
R116 and R115 deenergized, the windings of R116
and R115 are short-circuited over obvious paths.
2,135,822
When, however, R101 operates, it opens at RA108
a point in the path short-circuiting the winding
of R1I0, permitting the last-mentioned relay t0
operate and interrupt at RATII the path nor
mally short-circuiting the winding of R1 I5. The
relay R1 I5 in turn operates to complete, at RA1 I 6,
an obvious path for short-circuiting the winding
of R101, which latter relay now restores to re
complete at RA108 the path for short-circuiting
10 the winding of R1 I0. When R1I0 falls back, it in
turn recompletes at RA1|| the path for short
circuiting the winding R1| 5, and the last-men
tioned relay, upon restoring, opens, at RAlIB, a
point in the path short-circuiting R101. Thus.
15 the three relays noted, namely R101, R1I0 and
R1|5 operate sequentially and continuously so
long as R120 is held operated.
-
ment with their respective associated third con
tacts and R1|5 again operates, the paths noted
are again completed, since the second and third
contacts of each of the contact sets 19| to 193,
inclusive, are connected together. When, how
ever, the wipers of the switch 110 are stepped to
their respective third oE-normal positions, _the
above-'traced path for applying ringing voltage to
CI58 is broken at the wiper 113, since C|6I is not
connected to the fourth, ñfth, sixth and seventh 10
contacts of this contact set. Hence only two
short pulses of ringing voltage are applied to
C|58 during the period when the wiper 113 is
traversing the iirst six active contacts. In the
case of the contact set 192, however, it will be 15
noted that the conductor C|6| is connected‘to the
second, third and fourth contacts so that three
Each time R1I0 operates it not only functions `short pulses of ringing voltage are applied to
to open the path for short-circulting the winding C|54 during movement of the switch wipers over
20 of R1|5, but, in addition, completes a circuit for the first six active points. In the case of the 20
energizing M165 embodied in the rotary switch contact set 19|, wherein C|6| is connected to the
110. This circuit extends from ground at RA12| second, third, fourth and fifth contacts, four
by way of CI36, RA1|2, CI62 and through the short pulses are applied to the associated ringing
winding of M165 to battery. Thus M165 is caused current conductor CI51. It is noted here that
25 to drive its wipers 11| to 115, inclusive, at the movement of the switch wipers 11| to 115, inclu 25
rate of one step for each complete operating cycle sive, over six points represents a complete ringing
of the three relays R101, R1I0 and R1|5.
cycle. Thus, when the wiper 113 is stepped from‘
At any given time when the two relays R1I0 its sixth to its seventh off-normal position, a new
and R1| 5 are simultaneously in an energized con
cycle is started, since the eighth and ninth con
dition, paths are prepared for extending the volt
tacts of the set 193 are connected to CI6I in the 30
30
age developed across the secondary windings of manner previously described. In a similar man
the transformer 680 to each of the iive enumerated ner, when the wipers 112 and 11| are stepped
ringing current conductors. Thus, with th’ese two from their respective .sixth to their respective
relays in their respective operated positions CI38, seventh olf-normal positions, a new ringing cycle
y35 which extends to the ungrounded terminal of the is initiated. It will be apparent, therefore, that 35
transformer winding 68|, is connected by way of six complete operating cycles for the relays R101,
RC1I8, RA1I1, RA1|4 and C|63 to the common R1I0 and R1I5 are required to produce a com
conductor C|6| which extends to selected ones of
the various contacts in the three contact sets
19| to 193. By a proper selection and intercon
40 nection of the contacts to C|6|, ringing voltages,
interrupted in accordance with the characteristics
mentioned above, are applied to the respective
ringing current conductors.
For example, the
conductor C|58 is terminated atthe wiper 113 as
45 sociated with the contact set 193, and the com
mon conductor C|6| is connected to each of the
second, third, eighth, ninth, fourteenth, fifteenth,
twentieth and twenty-ñrst contacts of this set.
With the contacts of the set 193 thus connected,
50 the operation of the switch is characterized by
the application of voltage representing two shorts
to the conductor CI58.
Assuming the switch 110 is standing in the
position shown, when the cyclic operation of
55 R101, R1I0 and R1|5 is started, the above-traced
circuit for M165 is completed upon the initial
operation of R1 I0. As a result, the wipers 11| to
115 are stepped to their respective first olf-normal
positions so that the wiper 113 .engages its asso
60 ciated second contact.
Shortly thereafter, R1|5
operates to complete a path for applying ringing
voltage to CI58, this path extending from CI38
by way of RC1|8, RA1I1, RA1I4, CIGS, CIBI, the
second contact of the set 193 and the switch wiper
113 to CI58. Since the common conductor CI 6I
is also connected to the respective second con
tacts of the sets 19| and 192, this voltage is also
applied by way of the switch wipers 11| and 112,
respectively, to the ringing current conductors
CI51 and CI54. Shortly thereafter, and when
R101 operates, R1I0 restores to interrupt, at
RA1I4, a point in the above-traced path for
applying the voltage to CIGI. Thereafter, and
when R1I0 again operates to cause M165 to step
its associated wipers a second step or into engage
plete ringing cycle.
The method by which ringing voltage is applied
to C|56 for a relatively long time interval during
each ringing cycle thereby to provide a ringing
pulse representing one long, is slightly different
from that just described for the production of
pulses representing shorts. The production of
long pulses is under the control of R180, having
an operating circuit controlled by the wiper 114
in cooperation with its associated contacts.
Thus. during the various ringing cycles, the wiper
noted completes circuits extending by way of the
second, third, eighth, ninth, fourteenth, fifteenth,
twentieth and twenty-first contacts of the set 194
and C|60 for energizing the slow-to-release relay
R100. This relay, upon operating, completes at
RA184 and RC186, a path extending from C |38
for applying to C|56 the voltage developed across 55
the secondary winding 68|. Since the conductor
C|60 is multipled between the various enumer
ated contacts of the contact set 194, it will be
understood that R180 is caused to operate once
during each ringing cycle and is held operated for
the time interval required for the wiper 114 to
traverse two of its associated contacts. Due to
the prolonged portion of each ringing cycle when
R180 is energized, a voltage pulse` is applied to
C|56 during each ringing cycle which is of sufll
cient length to distinguish the same from the
short pulses applied to CI54, CI 51 and CI58.
With respect to the coded ringing voltage ap
plied to C|65 and comprising one long impulse
and one short impulse for each ringing cycle, it 70
will be noted that the long impulse is attained
through the operation of R180 directly to apply at
RA18| and RC183 the voltage on CI38 to the
ringing current conductor CI55. This long pulse
is held until the wiper 114 is stepped from engage 76
10
, 2,135,832
ment with its associated third contact and into
engagement with its associated fourth contact, at
which time the operating circuit for R100 is
opened and an alternative path is prepared, at
the switch wiper 112 and its associated fourth
contact, for applying a short pulse of voltage to
CI55. This path is completed upon the operation
of R1l5 and extends from C|00 by way of RC1I0,
RA1I1, RA1I4, Cl00, CISI, the fourth contact of
10 the. set 102, the switch wiper 112, RC102 and
RA10I to CI55. It is believed clear without fur
ther discussion that the production of this par
ticular code occurs once during each ringing
cycle.
15
»
Ground potential is, at all times, applied to
each of the ilve enumerated ringing current con
ductors for the purpose of energizing the ring
cut-oil' relays of the links in the manner de
scribed hereinafter. Thus, those contacts of each
of the contact sets 10| to 103, inclusive, excepting
the iirst contacts of each set, which are not active
in the paths for applying voltage to the ringing
current conductors, are grounded so that ground
is directly applied to the respective conductors
25 CI50. CIM and C|51 when the respective asso
ciated wipers are stepped into engagement there
with. For the same purpose, the armatures
RA1I0 and RA1I1, embodied respectively in the`
relays R1|0 and R1I5, are arranged to be oon
30 nected to ground, when restored, so that ground
may be applied to the active contacts of the con
tact sets 19| to 193, inclusive, for a portion of each
operating cycle of the relays R101, R1 i 0 and R1 I 5.
In a similar manner, the armature RA100 em
bodied in the relay R100 is arranged to be con
nected to ground at RC105 during those intervals
when R100 is restored, 'so that ground is extended
by way of the elements noted to C|50. Direct
current ground potential is also applied to each
40 of the iive enumerated conductors during the
periods when alternating ringing current voltage
is applied thereto, it being extended. during such
periods, from the grounded terminal of the trans
former winding 00| and by way of the conductor
45 C|00 to each of these conductors.
upper winding of R105. ' 'I‘his latter relay imme
diately operates to complete, at RA100 and RA101,
a circuit for energizing its lower winding. 'I‘he
two windings of R105, -like those of R100, are
connected in opposition so'that, when the above
notedxcircuit is completed, this relay restores to
open the operating circuit for its lower winding.
Immediately this occurs, the upper winding is
again effective and the relay reoperates. It will
be seen, therefore, that R105 functions in the
manner of a buzzer so long as R120 is held oper
ated. Each time R105 operates, it short-circuits,
at RA100 and RA101, the sexies circuit compris
ing the exchange battery and the resistor 102.
Hence, through the repeated operation of R105,
an alternating voltage is developed across the
resistor 102 which is impressed through the illter
choke 104 on the dial tone current conductor
CI5I. This current is generated so long as the
relay R120 is maintained in its operated position.
As noted previously,'the power and supervisory
apparatus includes means for controlling the con
nector portion of any seized link in its operation
to select an idle trunk outgoing from the ex
change I0 and following the dialing of the num
ber identifying the group of trunk lines. Speciil
cally, this means comprises the two relays R050
and R055, which function to apply ground pulses
to the several supervisory conductors C100, CI00',
etc. extending, respectively, to the control appa
ratus individually embodied in the several links
provided in the exchange I0. 'I'he operation of
these two relays to perform the function noted
is initiated when R120 operates to complete, at
RA12I, a circuit extending by way of CI00 for
ro
energizing the slow-to-release, slow-to-operate
relay R555. This relay, upon being energized,
operates after an interval to short-circuit at im
RA656 its operating winding and to complete at
RA051 an obvious circuit for energizing R050.
The last-mentioned relay now operates to com
plete, at its armatures' RA05I and RA052, etc.,
Referring now more particularly to the opera
tion of the relay R100, it is pointed out that this
paths for applying ground to the supervisory con- '
relay functions as a source of busy-tone current.
R655 has been short-circuited for an interval,
this relay restores, so that its winding is again
energized to cause its reoperation. During the
period of restoration, however, R550 is caused to 50
restore, so that ground is removed from the vari
ous supervisory conductors noted. It will be ap
preciated that the repeated operation and resto
ration of R055 to cause the repeated operation 55
and restoration of R050 continues so long as
ground is maintained on CISG, or, so long as R120
is held operated.
Thus, when the upper winding of this relay is
50 energized from ground at RA12I, upon operation
of R120, it operates to complete at RA10I a cir
cuit also extending from ground at RA12i for
energizing its lower winding. The two windings
of R100 are connected in opposition so that when
55 the lower winding thereof is energized, the relay
immediately restores to open at RA10| the circuit
for energizing its lower winding. -Immediately
this circuit is opened, the upper winding is eil'ec
tive to cause the relay to reoperate. Hence, it
60 will be seen that this relay operates in the inan
ner of a buzzer.
Each time R100 operates, it
short-circuits, at RA10I, the circuit comprising
the resistor 103 connected in series with the ex
change battery. Due to the repeated short-cir
65
voltage which comprises a dial tone current
source. Thus, when R120 operates, it completes,
at RA12I, an obvious circuit for energizing the
cuiting of these two series connected elements,
an 'alternating voltage is developed across the re
sistor 103, which is extended by way of the filter
choke 100 and the armature RA1|3 to the busy
tone conductor C I I1. From the above description
70 it will be` apparent that the cyclic operation of
R1|5 causes an interrupted busy-tone voltage to
be applied to the busy-tone conductor noted.
The relay R105 operates in a manner similar to
that just discussed with reference to R100 to
75 develop across the resistor 102 an alternating
ductors CHQ, CI30’, etc. After the winding of
'I'he timing device, referred to brieily above,
comprises more particularly the plurality of in~ 00
terrelated relays R124, R130, R135 and R140,
which relays are controlled by means including
the rotary switch 110. This device functions to
apply ground pulses to the supervisory leads CIN,
lCI“ and CI35 at spaced time intervals, which
ground pulses are utilized to cause the allotter
means illustrated in Fig. 6 to assign a new link
in search of a calling line in the event a first
assigned link fails to ñnd the calling line, and
further to cause a defective line to be locked out 70
of service. The particular portion of the switch
110 which enters into the operation of the timing
device comprises the contacts of the set 134 and
the associated wiper 110. Thus when R120 op
erates to initiate the operation of the switch 110 75
11
2,135,822
and when this switch steps its wipers to their
respective third oir-normal positions, a circuit is
completed at the switch wiper 114 for -energizing
R135, this circuit extending by way of the wiper
noted, the fourth contact of the set 194, CIBG,
RC146, RA144, and through the winding of R135
to battery. The relay R135, upon operating, com
pletes, at RA136, a path for applying ground to
the supervisory conductor or time pulse lead CI31.
10 This path extends from ground on CI22, RA129,
RA14I, RC142 and RA136 to CI31. The Vcomple
stepped from their respective third off-normal
When, however, R124 operates, ground is re
20 positions, the above-traced operating circuit for
R135 is broken at the switch wiper 1'l4,-causing
this relay to restore.
Thereafter, and when the switch wipers are
rotated into engagement with their respective as
sociated twenty-fourth contacts, a circuit is com
pleted for energizing R140, this circuit> extending
from ground on the switch wiper 114 by way‘of
the twenty-fourth contact of the set 194, CI68
and through the lower winding of R140 to bat
30 tery. The relay R140 now operates to complete
at RA141 a locking circuit for itself, which circuit
includes the upper winding of R140 and extends
from ground on CI22. At RA14I, the relay R140
opens a point in the above-traced path for ap
35 plying ground to CI31 and prepares a point in
the holding circuit for R135. At RA144 and
RC146, the relay R140 opens a point in the
above-traced operating circuit for R135 and pre
pares an alternative operating circuit therefor.
50
55
60
70
traced holding circuits for the relays R130, R135
and R140, causing these relays to restore. At
at this time due to the deenerglzed condition of
R140. When the wipers of the switch 110 are
tion of this path in the manner noted represents
45
ing, opens at RA120 a point in each of the above
RA129, the relay R124 prepares a holding circuit
for itself, which circuit is completed at RA131
before the slow-to-release relay R130 falls back
to restore its armature RA132. -In this connec
tion it is pointed out that the switch 114 stands
in engagement with its associated nineteenth
contact for a time interval sumcient to permit
each of the relays R130, R135, and R140 to re
store, and the relay R124 to be energized.
It will be noted that with R124 deenergized,
ground is normally applied from RA125 by way
of RC126 to the supervisory conductor CI49.
the first ground pulse applied to thev supervisory
conductor CI31. The relay R135, upon operat
ing, also prepares, at RA138, a locking circuit forA
itself, but this locking circuit is not rcompleted
40
circuit extends from ground on the wiper114 by
way of CI64, RA132, and through the winding of
R124 to battery. 'I'he relay R124, upon operat
moved from this conductor and is applied to the 20
supervisory conductor CI35 at> RC121. The op
eration of this armature to remove ground from
CI48 and to apply ground to CI35 is responsible
for certain of the supervisory operations re
ferred to more speciñcally in a following portion 25
of the speciñcation.
'
The relay R124 is held operated until such time
as the switch wiper 114 is again driven into en
gagement with the fourth contact of the set 194,
at which time the previously traced operating cir 30
cuit for R135 is completed. The relay RA135,
upon operating a third time, opens at RA131 the
above-traced holding circuit for RA124, causing
this relay immediately to restore. At RA136 the
relay RA135 prepares a point in the path de
scribed above for applying ground to the super
visory conductor CI31, this path being subse
quently completed when R124 restores its arma
ture RA128. Thus, a second ground pulse is ap
plied to C I 31 a deñnite time interval following the
application of the ñrst ground pulse to this con
ductor. In view of the preceding description, it
will be understood that the cyclic mode of opera
tion of the four relays R124, F130, R135 and R140
under the control of the switch 110 is continued
so long as R120 is held operated to maintain the
switch 110 in operation.
During continued operation of the switch 110
the wiper 114 is brought into engagement with
the twenty-third contact of the contact set 194
so that the last-mentioned operating circuit for
R135 is completed, this circuit extending from
ground on the wiper 114 by way of CI61, RC145,
RA144 and through the winding òf R135 to bat
tery. Upon operating the second time. R135 com
pletes at RA138 a holding circuit for itself, which
Asnoted above, rotation of the switch wipers
circuit extends from ground on CI22 by way of embodied in the switch 110 over twenty-five points
RA128, RA14I, RC143, RA138 and through the corresponds to the completion of four ringing
winding of R135 to battery. At RA 136, the relay cycles. In order that this switch shall be condi
R135 prepares a point in the above-traced path tioned to start a ringing cycle irrespective of when
for applying ground to CI31,- this path now being the power and supervisory apparatus is released,
open at RA14I and RC142 of the operated relay there is provided an alternative circuit for main
R140. At RA131, the relay R135 opens a point taining R120 energized independently of the con
in the holding circuit traced hereinafter for R124 dition of R420 embodied in the control apparatus
and at RA139 it prepares a point in the operat
of the link illustrated, or a corresponding relay
of another link. This circuit extends from ground
ing circuit for R130.
After a time interval during which the switch at the switch wiper 115 by way of CI59, RA122
110 continues to operate, the switch wiper 114 is and through the winding of R120 to battery. As
rotated into engagement -with the twenty-second shown, the conductor CI59 is connected to each
contact of the contact set 194, thereby to com
of the contacts of the contact set 195 correspond
plete a circuit extending by way of CI65 and ing to the active points of each of the other con
RA139 for energizing R130. The last-mentioned tact sets. Hence, if R420 is caused to restore to
relay, upon operating, completes, at RA13I, a remove ground from the start conductor CI22
holding circuit for itself and prepares, at RA132, while the wipers of the switch 110 are standing
a circuit for energizing R124. The holding cir
in their respective fourth off-normal positions,
cuit noted, namely. that forR130, extends from for example, the relay R120 is held energized over
ground on CI22 by way of RA129, RA13I and the circuit just described until the switch wipers
are rotated to their respective sixth olf-normal 70
through the winding of R130 to battery.
After a still further time interval during which positions, at which time this alternative circuit
the switch 110 continues vto operate, the wiper for R120 is interrupted, causing an interruption
in the cyclic operation of the control relays R101,
114 is driven into engagement with the nine
teenth contact of the set 194, thereby to complete R'II 0 and R1 I 5. There results the s‘topping of the
the above-noted operating circuit for R124, which switchI 110 with the wipers thereof standing in .. 75
Документ
Категория
Без категории
Просмотров
0
Размер файла
5 130 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа