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Патент USA US2403475

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July 9, 1946.
2,403,475
H. M. BAscoM E?AL
TELEPHONE sYs-TEM
5 sheets-sheet 1 '
Filed Jan. 15,: l1945
'
HM. @Asco/w
’N V5^’ T@RSF/1. HUBBARD
ATTORNEY“
July 9, 1946.
H. M. BASCOM ETAL
2,403,475 '
TELEPHONE SYSTEM
Filed Jan.y 13, 1945
,HMB/1560,14
’Nm/TOMBA. HUBBARD
B” Q? 6. M `
ATTORNEY
July 9, 1946.
`
HgM. BASCOM E-rAL
2,403,475
TELEPHONE SYSTEM
Filed Jan. 13, 1943
5 Sheets-Sheet 3
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By
H M BASCOM
FA. HUBBARD
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July 9,
` H_ M_
TELEPHONE
BASCOM
SYSTEM
ETAL
Filed Jan. l5, 1945
5 Sheetg-Sheet 4
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H. M. @ASCOM
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B_y 6.26. M
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„ -July 9, 1946.
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H. M_ZBAsc-OM l-:T Al. l
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2,403,475
TELEPHONE SYSTEM
Filed Jan. 15, 1945
- 5 sheets-sheet 5
FIG /4 -
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ATTORNEY
Patented _July9, 1946
2,463,415
~ UNITED STATES AParleur-T lori-‘ica
TELEPHONE SYSTEM
Henry M. Bascom, New York, N. Y., and Francis A.
Hubbard, Maplewood, N. J., assignors to Bell.
Telephone Laboratories, Incorporated, New
York, N. Y., a corporation of New York
Application January 13, 1943, Serial No. 472,202
y
_
'
7 Claims.
(Cl. 179-90)
lV
» This invention relates to telephone systems and
more particularly to a system ’employing a call
the major portion of the signal being consumed
in the functioning of the unit of the receiving
circuit which indicates that a signal is present
and which activates the»receiving channels of
the receiving'circuit for a period of 5 to 8 milli--
transmitter which is an improvement over the
telephone call transmitter disclosed in United
States Patent No. 2,315,344, granted March 30,
1943, to R. F. Mailina.
_
In the transmitter described in that applica~
tion a set of key members is used for actuating
U-shaped bars in predetermined combinations
for releasing normally pretensioned vibrative ele 10
ments or reeds in similar-combinations, by the
seconds.
Since it appears to be unusual for a
key stroke to be completed in less than 100 milli
seconds, it would therefore be entirely possible
to >secure two separate signals on each key
stroke.
The principal advantage which is gained from
operation of latch members or pawls normally
this method of operation islthat Íthe number of
holding the vibrative elements in their preten
vibrative elements may be reduced from ñve to
sinned- positions. the operation ofthe vibrative
three. since the selective release of the three
elements in the> magnetic ñeld of the generator 15 members may be made ñrst during _the down
being eiîective to transmit signals corresponding
stroke‘ of any key to send one signal impulse and
to the numerical values of’ the successively
again during the up-stroke of the key to send a
operated members.
‘
second signal impulse. The reduction of the
In this transmitter ñve vibrative elements
_number of vibrative elements enables- a corre
having five different fundamental frequencies are 20 sponding reduction of the number of receiving
employed which elements are released for/vibra
channels required in the receiving circuit at the
tion through the operation of five U-bars which _
'central
ofiice. This reduction permits the
are allocated respectively to the five vibrative
frequency spacing between channels to be
elements. 'I‘he U-bars are operated in different
doubled for the same outside frequency. range
combinations of two at a time by the depression 25 which would reduce the discrimination required
of the different keys of the ten-button key-set
from channel filters. For example, the channels
thereby resulting in the release of the vibrative
could be designed to be responsive to signals of
elements in corresponding combinations of two
the three frequencies 700. 1100 and 1500 and, of
at a time. The release of the vibrative elements
course, the vibrative elements of the call trans
occurs for a brief interval only during the de 30 mitter would be selected to cause the generation
pression movement of l a key-set key. The
of such frequencies. Alternatively. the outside
characteristics of the vibrative elements may be
frequency range could be made smaller so that
so chosen that their vibration in the magnetic
the difference in attenuation `between the highest
ñeld of the generator causes the generation of
and lowest frequencies would be less.
currents of, for example. 700, 900, 1100, 1300 and ì
1500 cycles.
Studies of this transmitter and the operation
thereof havey indicated to the applicants that
there would .be several advantages if the vibrative .
elements could be released for vibration either 40
-. during the down-stroke or the up-stroke _of an
It is, therefore, the object of the present in- v
vention to arrange a call transmitter of theree
leased reed type so that the reeds thereof are
selectively released on the down-stroke and on'
the up-stroke of any key of the key-set.
A further object of the invention is to enable
a wider spacing of the frequencies generated by
operated key-set key. The studies which have
a reed type call transmitter without increasing
been made of the time intervals required for the
the outside frequency range whereby a greater
satisfactory registration of the. signals trans
discrimination by the receiving channels is
mitted by a substation generator of the type 45 obtained.
4
just referred to and observations of the speed
An alternative object of the invention is to
with which the keys of the key-set are~ operated
enable a narrower outside frequency rangev of
indicates that it would be possible to generate a
the frequencies generated by' a reed type ycali
signal impulse which could be registered `accur
transmitter whereby the difference in attenua
atelyon either or both the down-stroke and the to tion between the'highest' and lowest frequencies
up-stroke of a key-set key. VIn receiving circuits
isA lessened.
which have been developed for use with the ca_ll
These objects are attained by the provision of ’
transmitter above referred to a signal duration
mechanism in a call transmitter of the type dis-'
of` 20 to 25 milliseconds or less is all that is util
closed in the patent to Mailina hereinbefore re
ized for effecting a registration of such. signal.
ferred to, whereby the operation ot anyone of
.
2,403,475
the ten keys o_f the key-set is eñective upon the
down-stroke to selectively release one of three I
vibrative elements or reeds and is effective upon
its up-stroke to selectively release one or more of
the three vibrative elements. In the proposed
transmitter only three vibratíve elements or reeds
are required. To pluck these reeds a releasing
mechanism of the improved type disclosed for
example in United States Patent No. 2,307,537,
granted January 5, 1943, to D. B. Parkinson, may
4
For a clearer understanding of the‘invention
reference may be had to the -following detailed
description taken in connection with the accom- '
panying drawings in which:
.
_
Fig. 1 is a side elevation view of the telephone
call transmitter embodying the invention, the
casing being shown with a portion broken away
to disclose the reeds in their pretensioned posi
tions and to disclose the key-operated reed-re
leasing mechanism;
Fig. 2 is a side elevation view similar to Fig. 1
but in which a portion .of the reed-releasing
ciated with each reed is operable by a cam four
mechanism is shown in the position assumed
times during each revolution of the cam. vEach
_upon the depression of a key and one of the
cam has two ratchet wheels connected thereto,
is shown released for vibration;
each of which ratchet wheels may be advanced 15 reeds
Fig. 3 is a top view of the call transmitter with
be employed. The_reed-releasing member asso
through four steps per revolution by an associ- '
ated stepping pawl which is pivoted to the end of
a portion of the casing broken away;
J
a pawl lever connected to a U-bar.
reed-releasing mechanism in the normal position
Fig. ‘i is an enlarged detail view showing a
The two
pawls associated with the two ratchet wheeis con
in which the associated reed is held pretensioned;
nected to each cam are disposed so that the cam 20
Fig. 5 is a detail view similar to Fig. 4 showing
is advanced one step or quarter `revolution upon
the reed-releasing mechanism in its operated po
the operation of the U-bar to which one of the
sition in which _the associated reed is freed for
two pawls is connected and may be advanced a
vibration;
second step or quarter revolution upon the re
Fig. 6 is a top plan view of the cams and as
lease of the U-bar to which the other of the two 25
for operating the
sociated ratchet assemblies
pawls is connected.
reed-releasing members;
Of the six U-bars thus required three are in
strumental when operated in response to the
Fig. '7 is a front elevation View of the cams and
associated ratchet assemblies;
down-stroke of certain keys of the key-set to
Fig. 8 is a side view, with a portion cut away,r
cause the selective _releasing of- the three reeds 30 of one of a pair of cam operating ratchet assem
and the other three are instrumental when re
blies shown in vits normal position and effectivel
leased in response 'to the up-stroke of certain
when moved to the position shoyvn in Fig. 9 upon
keys of the key-set to cause the selective releas
the down-strokeof a key-set key to rotate the
ing of the same three reeds. The selective re
associated cam when the operated key returns to
35
leasing of the reeds in response .to the down
'normal on its up-stroke;
strokes and 11p-strokes ofthe ten »key-set keys
Fig. 9 is a side view of the ratchet mechanism
causes the generation of signals of the three fre
shown
in Fig. 3 in the position to which it is
quencies a, b andV c which might, for example,
moved at the end of the down-stroke of a key
be of '700, 1100 and 1500 cycles frequency.
A code may be so selected with respect to the 40
standard arrangement of the keys >in the key-set
as indicated in a` table appearing hereinafter that '
set key;
`
Fig. v10 is a side view, with a portion cut away,
of the other of a pair of cam operating ratchet _
assemblies shown in its normal position and ef
every key releases a single reed on the down
fective during its movement to the position shown '
stroke and that no two adjacent keys arranged
in Fig. 11 in response to the down-stroke of a key
45
either vertically or horizontally release the same
set key to rotate the associated cam;
-reed on the down-stroke. Hence, if two keys are
Fig. 11 is a side view of the ratchet wheel as
depressed at once, two reeds will be released and
the receiving circuit can be arranged to recognize
this as a false signal.
_ sembly shown in Fig.
10 in the 'position to which
it. is moved at the fmd of the down-stroke of a
key; and
The transmission of two signal impulses by the 50 key-set
Figs. 12, 13 and 14 taken together show a tele
_call transmitter for each keyed digit requires a
phone system to which the improved call trans
modification of the receiving circuit associated
mitter is applicable; Fig. 12 showing the substa
with the central oilice sender, whereby three re
tion circuit in which the call transmitter is in
ceiving channels are provided to receive the three
diiîerent frequencies transmitted by ‘ the call
transmitter, with each of which channels two
groups of. recording relays are associated. Each
of these groups of relays comprises a relay corre
spending to each of the three frequencies, one
group being normally associated with the three
receiving channels so that one of such relays is
selectively operable in response to the'reception
of one of the three frequencies Vtransmitted upon
the down-stroke _of an operated key andthe other
group being associated with the three receiving
channels following the termination of the nrst
impulse of a digit signal so that relays of such
group are selectively operable in response tothe
reception of one or more of the three frequencies
transmitted upon the up-stroke of the operated
key. Thus upon the termination of the two im
pulses of a digit signal a relay of the first group
and one or two relays of the second group will re
stalled, a diagrammatic illustration of a line
iinder first selector, a sender link comprising a
trunk finder and a sender selector, and a portion
of the circuits of a central office sender; Fig. 13
showing the receiving channels of the sender, the
recording relays and other control relays; and
Fig. 14 showing certain of the sender registers
and progress relays associated therewith.
In the call transmitter of the invention as
shown in Figs. 1, 2 and 3, a base I is provided
having up-turned edges 2 to which the molded
casing 3 is attached. Secured to the base I is a
mounting plate l having up-turned ears 5 and 6
for supporting a shaft 1 on which the key mem
bers Kl to K10, inclusive, are pivotally mounted;
an up-turned and then in-turned bracket 8 upon
which the off-normal switch assembly 9 is se»
cured by the screws l0; an up-turned ear Il the
purpose of which will be later discussed, and an
up-turned plate l2. Each of the key members
main _operated to control the setting of a digit
75 KI to KID, inclusive, is normally and yieldably
register of the sender.
5 ,
.
`
6
other to provide pole faces between which'the'
maintained in the position disclosed in Fis. 1
bya retractile spring I3 each of .which springs
free ends of the reeds may vibrate. Positioned
is hooked at one of‘its ends to _a key member and
at the other of its ends to the upper edge of the
on the upper surface of the pole-piece PI is a
bracket member 28 having two downwardly ex
plate I2.
tending ears 29 between which the latchingmem
Also pivotally mounted ou the shaft 1 are six
U-bars BI to B6., inclusive, which are operable in
different combinations _upon the depression of
the key members. These bars are normally and
ber'30 is pivotally'supported on the pin 3l, 'I'he
previously described .elements of the generator
are clamped together-.by screws 33 which pass
freely through aligned holes in the bracket mem
’ yieldably held in the position disclosed in Fig. 1 l0
ber 28, pole-piece PI, magnet Ml, the reeds,
magnet M2 and into threaded holes in the pole
by retractile springs I4 which are hooked at one
of their ends to the upper edge of the plate l2
and at their other ends are hooked to the lugs
piece P2. Interposed between the` pole-piece P2
and the base plate 6 is a separator ät preferably
of non-magnetic material. The generator. as
sembly may be secured to the plate d in any suit
I5 of lever members I6, I'I,> I8, I9, 20 and 2|
which are secured to the U-bars BI, B2, B3, B4,
B5 and B8, respectively, as by rivets 22.
able manner as by screws (not shown) extending _
through holes in the plate and separator 34 into
A U-shaped oli-normal bar Bl is also pivoted
on the shaft ‘I and is held in operable relation
with each of the ten key members KI to Kill,
threaded holes in the pole-piece P2.
.I
Positioned between the pole-pieces Pl and P2
inclusive, by'a’retractile spring 23, hooked at
in the space between the ends of the magnets -
one of its ends to a lug on the lever 2li, secured to
the bariBl as by rivets and _at the other of> its
MI and M2 and the inner faces of the in~turned
ends of the pole-pieces is a coil 35 having a cen
ends to the plate l2. The lever 24 is effective
tral vsleeve through >which the reeds Re, Rb and
Rc extend with sufllcient clearance to permit them
to control the od-normal switch assembly el once
when any key ofthe key-set is operated on a
to vibrate freely.-
down-stroke through the operation of the off
normal bar Bl and again when the operated key
is released in an up-stroke.
_
_
The latching member 3b, as best disclosed in
Figs. 4 and 5, is substantially l.-shaped having .
ears Stat its ends which serve as bearing mem
v
'I'he off-normal switch assembly may be of the
type fully disclosed in the copending application
Serial No. 470,724, ñled December 31, 1942, in
" 30
bers by which the member is pivoted on the pin
3l. The vertically disposed arm 3l of the mem- 1
- ber 30 is normally positioned as disclosed _in Fig.
«l with its upper. edg'e positioned beneath the
the name of F. A. Hubbard. In general it com
prises a permanent magnet to the pole faces of
_ ends of the three reeds Ra, Rb and Rc. The hori--
which are attached two parallelly extending pole
zontal arm 38 of the latching member is ncr
pieces having aligned holes therethrough in '
which is supported a switch element 25 of the
mally engaged by the ends of leaf springs at can.
ried by the reed releasing members dit.
For releasing each of the reeds forv vibration
mercuryr contact type. A. switch element of this
type is disclosed in Patent No. 2,295,602, granted
September 15, 1942, to C. E. Pollard, Jr., and has
a releasing member ät, operating cam ¿il and a
pair of cam-operating ratchet assemblies ¿l2 and
the characteristic that when its armature is op
erated a contact member movingv therewi‘l-,hV
t3, are provided. The operating cams and asso
vciatecl ratchet assemblies are mounted for rota
quickly disengages a. back contact member and
tion on a pivot screw t2 which is supported in>
quickly engages a front contact. member, but that
the ear llv and in the bracket d4 which bracket
when the armature is lreleased the movable con
may be secured to the base plate él in any suit- ~
tact member is slow to break away from the front
able manner as by rivets d5. The releasing roem
contact member. Normally the switch element is '
bers di! are each provided with a slotted verti
prevented from operating in the ñeld of the iiux
cal arm tt, a horizontal latch-operating pro
set up by the permanent magnet, by a low re-`
jection ‘ll and a vertically extending reed-re
luctance shunt member 28 held in bridging en»
leasing finger 48. The members ¿it are supported
sagement with the pole-pieces of the off-normal
so for vertical movement on >rods 4a which-extend
switch assembly by a retractile spring 2l. The
through holes in the ear ll and bracket 44 and' -
` end of lever 24 is so positioned with respect ‘lo a
through the slots in the members et. For spac
cam surface on the shunt member 26 that when
the end of lever 24 is lowered in response to the
ing the members 40 for alignment with the reeds
with which they function respectively, tubular
down-stroke of any operated key, the shunt 'is-- 55 spacers 50 are- positioned on the rods 49; Each
- momentarily cammed away from the pole-‘pieces
releasing member 40 is normally held with the
-to permit one operating cycle of the switch ele
' end of its finger 48 engaged against the _reed with »
ment and that when the end of lever 24 is raised
which it cooperates v--to pretension such‘reed as
in response to`the up-stroke of the operated key,
disclosed in Fig. 4, by a leaf spring 5l which is
the shunt is vagain momentarily cammed> -awayA 60 secured at one end to the base plate 4 as 'by a
from the pole-pieces to permit a second operating
rivet 52 with its free end engaged beneath the
cycle of the switch element. The off-normal ~` member 40. The upper end of -the vertical arm
4switch assembly is effective to transfer the sub
46 of each member 40 is provider.. with a rounded
station line from the telephone subset tothe field
cam surface 53 which is normally engaged in
winding of the call transmitter generator as will 65 the depression between two lobes of the associ
be later described.
_
On the mounting plate 4 is a voltage generator
G provided with two permanentmagnets MI and
M2 between which are positioned three vibrative
_ elem nts or reeds Ra, Rb and Rc the character
istics of which are so chosen as to _give these ele
ated
Each
Voperating
operating
cam
cam
4I.V
4l ,is provided
~
with
.
four
camming lobes and is' secured to a 'sleeve 54.
Also secured .to the sleeve 54 on one _side of the
70 cam 4l is the ratchet wheel 55 _of a ratchet as
vsembly 42 and on the other side of the cam is
ments different natural periods of oscillation.
l.the ratchet wheel _56 of a ratchet assembly“,
Associated with the outer pole faces of the 'mag
each of which ratchet wheels is providedwith
net -are two L-shaped pole-pieces PI and P2, the f four teeth equally spaced> around its periphery.
short >arms of'which are in-turned towardl each 75
lAs disclosed in Figs. 8 and '9 each ratchetas
-
2,408,475
.
7
sembly 42 comprises a ratchet wheel 55 .with
which an L-shaped pawl 51 is adapted to cooper
ate. The pawl 51 is pivoted by the pin 6I Yto
the lower -end of a pawl arm 58, the upper end
of which is pivoted to the forwardly extending
arm of a lever member such as 2| which is in
.turn connected to one of the U-bars, such as
B5._ The pin 5i also extends through aligned
holes in the parallelly disposed walls of a hous
` thekeys -of the key-set the housing 55 is rotated
by the pawl arm 50 in a clockwise direction
whereby the paw1 59 normally engaged with a
tooth of the ratchet wheel 55 rotates such- ratchet
wheel and connected cam 4I through a quarter
revolution until the ratchet assembly 43 assumes
the position disclosed in Fig. 1l at which time the
U-bar has become fully depressed. When there
after the operated key is released resulting in the
ing 62 which embraces the faces of the ratchet 10 restoration of the depressed U-bar the pawl arm
50 moving upwardly causes a counter-clockwise
wheel 55. The housing is also provided with other
aligned holes through which extends the sleeve
rotation of the housing 66 and pawl 59 whereby
the pawl 59 moves freely over a tooth of the
ratchet wheel 55 without causing the rotation
walls of the housing are united by web 53 to .
which one end of a leaf spring 6d is secured, the 15 thereof.
54 on which the ratchet wheel 55 is secured. The
free end of such spring being engaged with one
arm of the pawl 51 whereby the other end of
such pawl is held yieldingly in engagement with
the periphery of the ratchet wheel 55.
_
By virtue of the journaling of the housing 52
on' the sleeve 54 and the pivoted connectionA of
the pawl arm 58 to such housing, the housing
and pawl 5l are rotated about the sleeve 55 as
From the -foregoing description of the ratchet
whee1 assemblies d2 and 43 it will be noted that
the assembly c3 causes a quarter revolution of
the associated cam ci on the down-stroke of a
key-set key and the consequent down-stroke of a
U-bar, such as B5, and that the assembly 42 causes
a quarter revolution of the associated cam 4i on
the up-stroke of an operated key and the conse
quent up-stroke of the previously operated U
bar.
Thus, U-bars Bl, B3 and B5 through which
25
the three ratchet assemblies 43 are operated, may
mal position of the pawl 51 with respect to the
an axis upon either the downward or the up
ward movement of the pawl arm 58. The nor
be considered to be down-stroke bars and the
teeth of the ratchet- wheel 55 is disclosed in Fig.
U-bars B2, B4 and B6 to which the three ratchet
8. When, however, a U-bar and lever member
assemblies 42 are operated may be considered
connected thereto are depressed by the depres
sion of one of the keys of the key-set the hous 30 to be up-stroke bars. l Any cam 4l' may thus
be rotated under the control of either an asso
ing 62 is rotated by the pawl arm 58 in a coun
ter-clockwise direction whereby the pawl 51 moves
freely over a tooth of the ratchet Wheel 55 With
ciated down-stroke U~bar, such as B5, or an as
sociated up-stroke U-bar, such as B5.
To illustrate the manner in which the call
out causing the rotation of such ratchet wheel ’
until, when the U-bar has become fully depressed,` 35 transmitter functions, it will be assumed that
the ratchet assembly assumes the position dis
closed in Fig. 9. In this position the end of
pawl 51 has been forced by the spring 64 to en
gage beneath a tooth of the ratchet wheel 55. -
When thereafter the operated key is released re
sulting in the restoration of the depressed U
bar, the pawl arm 58 moving upwardly causes a
clockwise rotation of the housing 62 and pawl
51, thereby causing a rotation of the ratchet
wheel 55 and associated cam 4| through a quar
ter of a revolution.
'
-
-
As disclosed in Figs; 10 and 11 each ratchet I
wheel assembly 43 comprises a. ratchet wheel.“
with which a pawl 59 is adapted to cooperate.
the key member Kl for transmitting impulses of
a code for the digit lis depressed. By reference
to the following table, it will be noted that for the
digit 1 it is necessary to transmit an impulse of
the frequency a during the down-stroke of the
key KI 'and to transmit a second impulse of the
frequency a during thev up-stroke of key member
Kl . To accomplish this the under-surface of the
key member Kl is provided with an extension i3
.which engages with the upper edges of both the
U-bars B6 and B5 so that upon the down-stroke
of the key member both of these U-bars are de
pressed. The depression of the U-bar B5 through
the associated lever member 25 and pawl‘ arm
6u causesv a quarter revolution of the camv 4I
The pawl 59 is pivoted bythe pin 55 to the 50 which
momentarily depresses the releasing mem
lower end of a pawl arm 50 the upper end of
which is pivoted to the forwardly extending arm
. of a lever member, such as 20, which is, in turn,
connected to one of the U-bars, such as B5. The
` ber 40 associated therewith and with'the gen
erator reed Ra.' Upon the downward movement
of the member 40 the spring 39 is moved away
the horizontal arm 38 ot the latching mem
pin 65 also extends through aligned holes in the 55 from
ber
30,
the end of ñnger 43 is moved away from
parallelly disposed'walis of a housing 55 which
the reed Ra to permit the reed to engage- with the
embraces the faces of the ratchet wheel 55. The
upper edge of the vertical arm 31 of’ the member
housing is also provided with other aligned holes
30 and thereafter the projection 41 of member
through which extends the sleeve 54 on which
40 engages the horizontal arm 38 of member”
the ratchet wheel 56 is secured. The walls of 60 to rotate such member about the pivot pin 3| to
the housingv are united by a web 51 to which
remove its vertical arm 31 from beneath the end
one end of a leaf spring 58 is secured, the other
of the reed. The Reed Ra is thereby freed from
end of such spring being engaged with the pawl
59 whereby the pawl is held yieldingly in engage
ment with the periphery of the ratchet wheel 55.
By virtue of the'journaling of the housing 55
on the sleeve 54 and the pivoted connection of
its pretensioned position and vibrates within the
coil 35 and between the pole-pieces PI and P2 of
the generator G, Current of the frequency a is
thereby generated in the coil 35 and transmitted
therefrom over the substation line.
the pawl arm 60 to such housing, the housing
When the releasing member 40 restores to its
and pawl 53 are rotated about the sleeve 54 as an
normal
position under the influence of the spring
70
axis upon either the downward or the upward
movement of the `pawl arm 60. The normal po
sition of the pawl 53 with respect to a. tooth of
5i after the operating cam 4l has completed a »
quarter revolution under control of the down
stroke movement of the U-bar B5, the end of
the ratchet wheel 55 is disclosed in Fig. 10. When,
finger 48 engages with the reed Ra, damps its
howeven' a U-bar and lever member connected
thereto 'are depressed by the depression of one of 75 vibration and restores it to its pretensioned po
2,408,475
9
,
sition and the spring 3s carried by the member
4l engaging with the arm 38 of the latching mem
ber 30 moves the vertical arm of such member
beneath the end of the reed as disclosed in -Fig. 4.
The depression of the U-bar B6 through the
associated lever member 2| and pawl arm 58 lis
ineßective to rotate the cam 4| during such
down-stroke movement of the bar but the pawl
51 of the ratchet assembly 42 is so positioned that
upon the up-stroke movement ofthe bar B8 when
the key Kl is released, it is eii'ective to rotate the ‘
cam 4| through a second quarter revolution and
` to thereby again cause the release of the reed Ra ’
in the manner previously described to generate
a second impulse of `current of the frequency a
and to transmit it over the substation line.
10
,
larger areas cnice codes require two or three ofiice
code digit registrations and the numerical part of
the designation usually requires four registra
tions. In the present disclosure three cnice code
digit registers A,.B and C are shown inFig. 14 and
the units numerical register U is also shown, it
being understood that the thousands, hundreds
and tens'registers would be provided vand inserted
between the units register U .and the code digit
register C. These registers each comprise five
register relays which are selectively operated un
der the-control of the six recording relays AD,
BD, CD, AU, BU, and CU, and the frequency re-y
ceiving channels Fa, Fb and Fc of Fig, 13.
vIt will be assumed that the subscriber at the
substation illustrated in Fig. 12 -I removes the
The keys Kl to K|0, inclusive, of the key-set
handset H of the subset from the cradle to initiate
are so designed that they are effective to operate
a call whereupon a circuit is established over the‘
the U-bars BI to B6, inclusive, to control the gen
substationl line to thev central office' which is ln- '
eration o_f current of the frequencies a, b and c 20 strumental in causing the line finder
to hunt
in the manner indicated in the following table:
for and establish a connection with the calling
line, whereafter the line-finder first selector link
Key
becomesA associated over the sender link ,SL com
prising the trunk finder TF and the sender selec
K1
K2
K3
K4
K5
"25 tor SS with an idle sender. Upon the association
Umbau;operatedfn Baise 133,134 B1,B2 152,133
Down-stroke ire
quency ......... ._
Up-stroke
av
c
b
l
c
fre-
Y of the sender with the substation a circuit is es-`
tablished from battery over brushes of the trunk A
finder TF and sender selector SS, conductor |200, ,
132,135
~
a
,
and windings of relay |300 to ground. Relay |300
.
'quency ......... ._
a
c
_
b
b
b
30 operates and closes an obvious operating circuit y
for relay |302. Relay |302 upon operating con
nects ground over its right contacts to the 011-.
normal conductor |303 to provide locking ground .¿
for other relays of the sender and over its left con
itacts and conductor |304 establishes the circuit of
Key
Ke
K7
7K8,
~
Ke
K10
relay
Y Ufbarsoperated-._- 133,136 B1,B6 B4,B5 B4,Bl B2, B3, B6
Down-stroke frequency.` ........ _.
Up-stroke fre
quency _________ ._
.
c
b
a
a
a
c
b
c
c
b
+
a
The call transmitter of Figs. 1 _to 11, inclusive, is
applicable to a, wide variety of types of dial
switching systems and, particularly to those of
|20|.
t
.
'
With ground connected to conductor |303 a cir
cuit is established therefrom over the left back
contact of relay |309, conductor |3|0 to battery
through the winding of lprogress relay i406
whereupon relay |408 operates and locks in a cir
cuit from battery` through its winding and the
winding of progress .relay |401, over the inner left ’
front contacts of relay |403 and over the back
the type _in which register mechanisms are em 45
contact of 'progress relay i4|1 to ground` on con
ployed at the central oiiice for registering the des- '
ignation transmitted and for controlling these- '
lective operation of automatic switches to com
plete connections. Accordingly, Y the system
chosen to illustrate the invention is one in which
`ductor |303. Relay |401 does not operate in this
locking circuit'since its winding is shunted so
long as ground remains connected to conductor
|3|0. lWhen relay |406 operates a circuit is also
50 established from ground on conductor |303, over
the central oflice is equipped with automatic
the back contact of. relay I4 | 1, the outer left con
switches of the panel type and with register send
tacts of relay |406, conductor |3I | and to battery
ers for registering the designations transmitted
through the right normal contacts and winding of
to the central ofiice from subscribers’ stations. It
relay |309. Relay |309 thereupon operates, locks
will be obvious that other formsof switches may 55 over its right’alternatecontacts to ground on
be used for establishing the connections such as
conductor |303 and at its back contact removes
switches of the cross bar type and switches of the
ground
from conductor |3|0 whereupon relay
well-known step-by-step type. _
|401 operates in the locking circuit of relay |406;
Referring to Figs. 12, 13 and 14 of the drawings,
prepares operating circuits for the relays of the .
a subscriber’s line is shown appearing in the con 60
first code digit register A over Aconductors |33l,
tact bank of the line finder LF. The line finder
|332, |334, |335 and |330 and at its right con
is joined to a first or district selector S and these
tact connects ground to conductor |30| to shunt
two switches together form a link for extending
the right winding of relay |300 whereby the cur
subscribers’ lines to trunks extending to other se
rent flowing over the operating circuit of relay
lectors (not shown) by which a connection from 65 |300 is increased as a signal to the line-finder
a calling subscriber’s line may be extended to a
selector link.
wanted subscriber’s line. The line _finder and
Relay I20| upon operating connects the wind
district link have access through a sender link
ings of battery feed relay |202 tothe calling line
SL comprising a trunk finder TF and a sender
substation over a circuit which may be traced
selector SS to a plurality of' common register 70 from batterythrough the left winding of relay
senders. Figs. 13 and 14 disclose such parts of a
|202, the left contacts of relay |20I, brush |203 of
sender as are necessary for an understanding of ,
the present invention. The number of registers
employed in these senders will vary with the re
quirements of Ithe exchange area. In ‘some of the'
sender selector SS, brush |204 of the trunk finder
TF, contacts of sequence switch -cam |205, brush
|208 of line finder LF, the ring conductor of the
calling line, switchhook contacts |201, the back
2,403,475
i
. ll
contact of the off-normal switch assembly 9,
through the transmitter |206, the left winding of
repeating'coil |209, the tip conductor of the call
ing line, brush I2 I0 of the line-finder LF, sequence
switch contacts |2| I, brush I2|2 of trunk finder
TF, brush |2|3‘ of sender selector SS, right con
coil |2|5 from 'the calling line loop 'to discon
tinue the application of dial tone current there
over- and connectsrdirect ground to the calling
line loop. - ’I'he removal of ground from conductor
|2 I1 removes the shunt from the winding of relay
|300 which now operates in a circuit from ground
_on conductor |303, over the upper alternate con
tacts of relay |20|, right winding of relay |202,
tacts of relay |305, through the winding of relay
normal contacts of relay I2|0 to ground through
|306 and resistance |308 to battery.
the secondary winding of the dial tone coil I2I5.
Relay v|202 operates over this circuit and dialing l0 When the first impulse of current of the fre
vquency c is transmitted over the line, -it passes
tone current is applied thereover to apprise the
over the 'previously traced circuit through the
calling subscriber that he may proceed to key up
sender link, through the broadband-pass filter
the digits of the desired telephone number. Re
I2|§ and the primary winding of the transformer
lay |202, upon operating, establishes an obvious
|220 and is impressed through the circuit X and
circuit for relay I2|0 which also operates to pre
the primary windings of the input transformers
pare an operating circuit for relay |2I4, and relay
associated with the receiving channels Fa, Fb, Fc
|202 establishes a circuit from ground over its
and V. Associated with each input transformer,
left contacts, conductor 12H, cver‘the upper nor
such as ISIS, is a frequency receiving channel
mal contacts and through the winding of relay
|305,'and through resistance i301 to battery and 20 consisting of a secondary winding of such trans
former, a series tuned circuit I3 I4, a single vacu
um tube such as I3I5 with a feedback through
the copper-oxide units, such as I3|6, and a relay,
operates and locks over its upper alternate con
such as |3|l. Initially, the vacuum tube is biased
tacts to ground on conductor |303 but the wind
ing of relay |306 being shunted so long as ground 25 nearly to cut-off. A small received signal is am
' in parallel therewith through the winding of relay
I 306 and resistance |308 to battery. Relay |306
is applied to conductor |2I1, does not operate.
The closure of the lower front contact of relay
|305 is without function at this time.
In response to the reception of dial tone the
pliñed andfed back. through the condenser I3I8
and the copper-oxide units |3|6 to charge up the
condenser I3|9. This condenser is poled to re
duce the negative bias on the grid of the tube |3|5
calling subscriber proceeds to key up the digits 30 with the result that the gain of the tube is in
creased and the amount of voltage on the grid
of the wanted line number, which number it will
is increased further. The rlnal result is that a rel
be assumed is CH3-1067. When the key K2 which,
in addition to the digit value 2 has the letter - atlvely small signal is suiiicient to produce a sharp
rise in plate current through the relay |3|l. The
designations ABC, is depressed to transmit signal
impulses for the first code letter C, the off-normal 35 sensitivity of each individual channel is adjusted -
switch assembly 9 is momentarily operated and
then released during the down-stroke of the key
and in the interval that the movable contact of
such switch assembly is in engagement with the
by means of the variable resistance, such as |320.
and during the interval that the movable con @n ~Jl
tact thereof is in engagement with its front con
tact, a reed will be vibrated to generate a second
current impulse of a predetermined frequency.
sumed that the `first channel Fa is tuned to the a
By referring to the preceding table, it will be
noted that when key K2 is depressed, the fre 00
of 1500 cycles.
This method controls the sensitivity by changing
the alternating current feedback and does not
affect the tuning of the channel.
From the preceding description it will be- ap
front contact thereof a reed of the generator G 40
parent that each relay, such as relay |3Il in
is caused to vibrate to generate a current impulse
each channel, will respond to a single frequency
cfa predetermined frequency. Again when the
with a relatively high discrimination against the
_ depressed key is released the off-normal switch
others. In the present description it has been as
assembly' 0 is momentarily operated and released
frequency of 700 cycles; the second channel Fb
is tuned to the b frequency of 1100 cycles; and
the third channel Fc is tuned to the c frequency
,
'
Upon the receipt of the first impulse of fre
quency c the channel Fc responds resulting in
quency c is generated both upon the down and up
the operation of channel relay 63H. Relay |3|l
strokes thereof. 'I'his frequency might', for ex
upon operating establishes a circuit from ground
ample, be of 1100 cycles.
4
over its contacts, the middle right back contact
The movement of the movable contact of the
off-normal swltch'assembly S from its back or 55 oi' transfer relay I 32|, through the winding of
recording relay CD to battery. Relay CD there
normal contact position disconnects the subset
upon operates, locks over its inner left contacts
transmitter |200 from its bridged connection
to ground over the back contact of release relay
across the substation line and the engagement of
|322 and at its outer left contacts prepares a cir
the movable contact with the front contact con
cuitfor relay |32I. Upon the termination of the
nects the coil 35 of the call transmitter generator
signal impulse when the off-normal switch as
G across the line through the condenser |2|8.
sembly 9 reestablishes the direct current bridge at
There being no direct current bridge across the
thesubstation through the subset transmitter, re
substation line at the substation so long as the
lay |202 reoperates to establish the circuit of re
movable contact of the off-normal switch assem
lay |2|6 and to reconnect ground to conductor
bly 9 is out of engagement with its back contact,
I2I1 whereupon such ground islextended over the _
relay |202 of the sender releases in turn opening
upper front contact of relay |306 to a point be
the circuit of relay |2| 6 and removing ground
_tween the winding of'relay |305 and resistance
from conductor |2|1. Relay |2|6, however, being
|301. Relay |305 being now shunted releases..
slow to release does not release during the inter
val that the movable contact of the off-normal 10 Relay |306 is, however, maintained operated fol
lowing the release of relay |305 over a circuit
switch assembly 9 is disengaged from its back
from ground on conductor I2I'l, over the upper
contact. With relay |202 released and relay |2|6
normal contacts of relay |305, through the wind
operated an obvious circuit is established‘for re
ing' 0f relay |306, and resistance |308 to bat
lay |2I4 which operates and at its contacts dis
connects the secondary winding of the dial tone u tery. With relay |305 released and relay |366
@£08,475 V
‘
„
-
_
13-
heldl operated the circuit or relay |32| is now
completed from ground over the lower back con
.tact of relay |305, the inner lower front contact
of relay |305, the outer left contacts of relay CD
tol battery through the- winding of relay |32|.
Relay |32| now operates; locks over its inner
right front contact to ground over the back con
' «tact of relay |322; at its back contacts disconnects '
14
normal switch assembly '0 is operated momen
tarily to open the direct current loop at the sub
station and to connect the generator G to the
substation line. During the interval that the
switch is thus operated the reed Rc is released to
4transmit an impulse of the frequency c which,
upon being received in the receiving channel Fc
of the sender results in the operation of channel
relay |3|`| and. _with transfer relays |32| Anow
the Iwindings of recording relays AD, BD and-CD
from the contacts of the channel relays |323, |324 10 released, in the operationof recording relay CD
and |3|‘|, respectively; connects the windings of
over-_the circuit previously traced. Relay CD up
recording relays AU,` BU and CU with the contacts
on operating locks under the control of relay |322
yof the channel relays, all of which are at this
and prepa-res thecircuit of relay |32| as previ
time released, and at its outer right front con
ously described. When the line loop is opened '
tact prepares a circuit for relay |322.
'
During the transmission of the second signal
impulse assumed to be also of the frequency c
the oil-normal spring assembly 9 being again op
erated momentarily, relay |202 again releases to
at the substation by the-oil'-normal switch as
sembly, relay |202 releases and by removing
j ground from conductor î|2|'| permits relay |303
to _operate in the manner previously described.
With relays |305- and |305 now both operated and
remove ground from conductor |2|1 thereby re 21) relay |325 operated, a circuit, is established from
leasing relay |305. Channel circuit Fc again re
ground over the lower 4~front contact of relay
sponds to the receipt of the frequency c and the
|305, the lower front contactv of relay |305, thel A
channel relay |3|`| upon loperating and with trans
fer relay |32| operated establishes a circuit from
ground over'the contacts of relay | 3| 1, the middle right front contact of relay |32| to battery
throughjthe winding of -recording relay CU. Re
lay CU fupon operating locks over its left front
contact to ground over the back contact of relay
,
left contacts of relay |325, conductor |3|2, the
right front contact of progress relay |405 to bat»,
tery through the winding of progress relay |4|0
which operates and locksthrough its winding
, and the winding of progress relay |4|1 over the
left contacts of relay |4|8 and the back contact
of progress relay |421 to ground on conductor
|322.
30 |303. Relay |4|1 being shunted so long as
When the off-normal spring assembly 0 again
ground remains connected to conductor |3|2,
releases to terminate the second frequency im
does not operate.
pulse the reoperation of relay |305 over the cir
At the end- of the iirst impulse for the second
cuit previously traced is effected by the reopera
code digit, with the off-normal switch assembly
tion of relay |202. With relay |305 operated and
' 0 restored, the transmission of the frequency c
relay |305 unoperated a circuit is established
ceases, channel relay |3|1 releases, and the di
from ground over the lower front contact of relay
rectcurrent loop is reestablished at the substa- |305, the lower back contact of relay |300, the
ytion resulting in the reoperation of relay |202 and
- right-backl contact of relay AD,` the No. 2 right
the reconnection of ground to conductor | 2| 1.
back contact of relayBD, the No. 2 right front 40 As before described relay |306 is now held oper
contact of operated relay CD, the No; 2 right back ~
ated to this `ground and relayv |305 is shunted
contact of relay AU, the No. 3 right back contact
and releases. With relay |305 released and relay
of relay BU, the No. 5 right front contact of op
|306 operated, the circuit for transfer relay |32|,
erated relay CU, 'conductor |332, the No. 3 'left
previously` prepared through the operation of
contacts of progress -relay |401, to battery through 45 recording relay CD, is completed and relay |32|
the -right winding of relay |402 'of the A code
operates and locks as previously described under
digit register. Relay |402 thereupon operates
the control of relay |322. Relay |305 upon re
and locks over its left winding and left contacts
leasing
also removes ground from conductor |3|2
to ground on conductor |303 and with the remain
whereupon progress relay |4|1 operates in the
ing relays |40|-, |404, |405 and |400 of the A reg 50 locking circuitof relay MIB; connects the Wind
ister unoperated, serves to register the ñrst
ings of the relays of the B code digit register to
code letter C.
,
,
conductors |33I, -|332, |334, |335 and |330, ex
A circuit is also established upon the operation
tending to contacts of the recording relays and
of relay |305 over its lower front contact. the lower
back contact of relay |306, over the outer right 55 at its right back contacts opens the locking circuit
of relays |405 and |401 which now release since
front contact of relay |32| to battery through
their operating circuit was openedl upon the
the winding of relay |322, which operates _after
previous operation of relay |309.
'
an interval sufficient to insure that the digit sig
Upon the up-stroke of the depressed key K4
nals recorded through the operation of recording
the'
off-normal switch assembly 9 is 'again oper
relays have been eiïective to cause the registra -60
ated momentarily to open the direct current loop
tion thereof in a digit register of the sender; at
at the substation and to connect the generator G
its back contact .opens the locking circuits .of
tothe substation line. During the interval that
the operated recording relays, in the case assumed
the switch is thus operated the reed Rb is re
relays CD and CU, which thereupon release; opens
the locking circuit of tr‘ansfer relay |32| 'which 65 leased to transmit the frequency b which upon
being received in the receiving channel Fb of the
releases and at its ‘front contact establishes an
obvious circuit for relay |325. Relay |325 oper
sender results in the operation of channel relay
ates, locks over its right contacts to oñ-normal
|324 and, with transfer relay |32| now oper
ground on conductor |303- and at its left con
ated, in the operation of recording relay BU over
tacts prepares a 'circuit for operating the progress
a circuit extending from ground over the con
relay |4|6. When relay |32| releases relay |322 70 tacts of relay _| 324, the inner left front contacty
also releases.
of relay |32| to battery through the winding of
When the subscriber depresses the key K4 to
relay BU. Relay BU upon operatingv locksover
transmit impulses for the second oiTlce code let
its left contacts under the control of relay |322.
ter H which has a numerical value of 4, the off 75 With the direct current loop now open at the
2,403,475
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15
substation, relay |202 releases followed by the
release of relay |306 as previously described.
When the off-normal switch assembly 9 again
' releases to terminate the second frequency im
pulse, relay |202 again operates thereby causing
the reoperation of relay |305 over the circuit
previously traced. With relay |305 operated and
relay |306 unoperated, a circuit is established
from ground over the lower front contact of
relay |305, the lower back contact of relay |306,
the right back contact of relay AD, the No. 2 back
contact of relay BD, the- No. 2 front contact of
relay CD, the No. 2 back contact of relay A‘Ug’the
l5
connection of groundy to conductor |2|'|. As be
fore described, relay |305 is now held operated
to this ground and relay|305 is shunted and re
leases. With relay |305 released and relay |306
operated a circuit for transfer relay |32|, previ
ously prepared through the operation of record
ing relay BD, is completed and relay |32| oper
ates and locks as previously described under the
control of relay |322. Relay |305 upon releasing
also removes ground from conductor |3|2 where
upon progress relay 5421 operates in the locking
circuit of relay |423; connects the windings of
, the relays of the C code digit register to conduc
tors |33l, |332, |334, |335 and |330 extending to
No. 3 front contact of relay BU, the No. 4 back
contacts of the recording relays and at its right
l5
contact of relay CU, conductor |334, the No. 4
back contact opens the locking circuit of relays
front contacts of progress relay |4|1 to battery
through the right winding of relay | 4| 4 ofthe
oilice code register B. Relay |4|¢l upon operat
|4|6 and |4|1 which now release since their 0p
erating circuit was opened upon the removal of
ground from conductor I3 I 2.
ing in this circuit locks over its left winding and
Upon the up-stroke of the depressed key K3 the
left contacts to ground on conductor |303 and 20 off-normal switch assembly 9 is again operated
with the remaining relays of the B _register un
momentarily to open the direct current loop at
operated serves to register the second oiflce code
the substation and to connect the generator G
letter H.
_
to the substation line. During the interval that
The operation of relay |305 with relay |306 un
the switch is thus operated the reed Rb is re
operated also establishes the previously traced 25 leased to transmit the frequency b which upon
circuit for relay |322 which operates after an
being received in the receiving channel Fb of the
interval to cause the release of the operated re
sender results in the operation of the channel
cording relays CB and BU and the release _of the
relay |324 and, with transfer relay | 32| oper
transfer relay |32|. When relay |32| releases,
relay |322 also releases.
` - y
ated, in the operation of recording relay BU.
30 Relay BU upon operating locks over its left con
When the subscriber depresses the key K3 to
tacts under the control of relay | 322.
transmit impulses for the third code digit 3, the
When the olf-normal switch assembly 9 again
off-normal switch assembly 9 is operatedmomen
releases to terminate the second frequency irn
tarily to open the directcurrent loop at the sub
pulse, relay |202 again operates thereby causing
station and to connect the generator G to the 35 the reoperation of relay |305 over the circuit
substation line. During the interval that the
previously traced. With relay |305 operated and
switch is thus operated the reed Rb is released
relay |306 unoperated, a iirst circuit is estab
' to transmit an impulse of the frequency b which
upon being received in the receiving channel Fb
of the sender results in the operation of the chan
nel relay |324 and, with transfer relay |32i not
operated, in the operation of recording relay BD
over a circuit extending from ground over the
contacts of relay |324, the inner left back con
\ tact of relay |32| to battery through the winding
lished from ground over the lower front contact
of relay |305, the lower back contact of relay
` i306, the right back contact of relay AD, the No.
3 right front contact of relay BD, the No, 3 right
back contact‘of relay CD, the No, 3 right back
Contact of relay AU, the No. 5 right front contact
of relay BU, the No. 6 right back contact of relay
CU, conductor |33l, the No, 2 left contacts of
progress relay to battery through the right wind~
of relay BD. Relay BD upon operating locks
under the control of relay |322 and prepares the»_
ing of relay |42| of the code digit register C, and
circuit of relay |32I as previously described.
a second circuit is established from ground ap
When the line loop is opened at the substation
plied over the right back contact of relay AD, the
50
by the olf-normal switch assembly relay |202 re
No. 4 right front contact of relay BD, the No. 4
leases and by removing ground from conductor
rightback contact of relay CD, the No. 4 right
|2|1 permits relay |305 to operate in the man
‘back contact of relay AU, the No. 7 right front
ner previously described. With relays |305 and
contact of relay BU, the No. 5 right back contact
|306 now both operated and relay |325 operated,
of relay CU, conductor |332, the No. 3 left con
a circuit is established from ground over the 55 tacts of progress relay |421 to battery through the
lower front contact of relay |305, the lower front
right winding of relay |422 of the code digit regis
contact of relay |306, the left contacts of relay
ter C. Relays |42| and |422 upon operating lock
|325, conductor |3|2, the right back contact of
over their left windings and left contacts to
relay |406, the right front contact of relay |4|6,
ground on conductor` |303 and with the other re
60
to battery through the winding of progress Vrelay
lays of the C code digit register unoperated serve
|426. Relay |426 operates and locks through its
to register the third cnice code digit 3.
winding and the winding of progress relay |421,
'I'he operation of relay |305 with relay |306
Vover the left contacts of relay |426 and to ground
unoperated also establishes the previously traced
on conductor |303, over the back contact of the
circuit of relay |322 which operates after an in
progress relay- (not shown) associated with the 65 terval to cause the release of the operated re
thousands digit register and corresponding to
cording relays BD and BU and the release of
progress relay |421. Progress relay |421 being
transferrelay |32| followed by the release of
shunted does not operate so long as ground re
relay |322.
mains connected to conductor |3|2.'
` In a similar manner in response to the keying
At 'the end of .the first impulse `for the _third 70 of the thousands numerical digit 1 two impulses
code digit with the off-normal switch assembly 9
Iof frequency a are sent resulting in the operation
restored, the- transmission of the frequency b
of recording relaysAD and AU. In response t0
ceases, channel relay |324 releases and the direct
the keying of the hundreds digit 0 an impulse oi
current loop is reestablished at the substation re
Afrequency c followed by an impulse _of frequencies
sulting in the reoperation of relay |202 and re 76
2,403,475
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17
18
a and b are sent resulting in the operation of re
cording relays CD, AU and BU. In response to
the keying of the tensdigit Gan impulse of fre
quency c followed by an impulse of frequency a
are sent resulting in the operation of recording
relays CD and AU and in response to the keying
of the units digit 7 an impulse of frequency b
followed by an impulse of frequency _a are sentv
resulting in the operation of recording relays BD ,
and AU.
,
With recording relays AD and AU operated to
record- the receipt' of signal impulses for the
-
. With recording relays BD and AU _operated to
record the receipt of signal impulses for the units
- digit 7, then when ground is applied to the right
io
armature of relay AD, a first circuit is completed over the right back contact of relay AD, the No. 4
right front contact of relay BD, the No, 4 right
back contact of relayiCD, the No. 4 right front
contact of relay AU, the No. 6 right backcon- l
tact of relay BU, the No, 5 right back contact of
relay CU, over conductor |332 and- thence over
the No. 3 contacts of the operated progress- relay
|461, to battery through the> right winding of
thousands digit 1, then when ground ls applied
relay |462 of the units digit register U. A sec
to the right armature of relay vAD, a circuit is
ond circuit is also completed over Ithe right back
established over the right front contact of relay
contact of relay AD, the No. 3 right front contact
AD, the No. 1 right back contact of relay BD,
of relay BD, the No. 3 right back contact of relay
the No. 1 right back contact of relay CD, the No.
CD, the No. 3 right front contact of relay AU,
- l iight front contact of relay AU, the No. 2 right
the No. 4 right back contact of relay BU, the No.
back contact of relay BU, the No. 6 right back
l right back contact of relay CU, conductor i335
contact of relay CU to conductor |33| and thence 20 and thence over the No. 5 contacts of relay i461
over the No, 2 left contacts of an operated prog
to battery through the right winding of relay
' ress relay, similar to relay |401 but associated
|465 of the units digit register U. Relays |452-
with the thousands digit 'reglster, to battery
through the winding of a relay of that register
corresponding to relay |40| whereby such relay 25
operates and locks and with the other relays
of such register unoperated registers the- thou
and |465 upon operating lock over their left
windings and left contacts to ground on con
.ductor |303 and with the _other relays of this reg
ister unoperated serve to register the units digit 7 .
All of the digits of .the wanted line number
keyed by the subscriber are now registered in
With the recording relays CD, AU and BU op- the sender and the sender may proceed to control
erated to record the receipt of signal impulses 30 selector switches to extend a connection over the
for the hundreds digit 0 then when ground is
district selector S and over other selectors, not
, sands digit 1.
applied to the right armature of relay AD, a. cir
shown, in accordance therewith, after which the
cuit is established over the right back contact of
sender link SL is released to release the sender
relay AD, the No. 2 right back contact of relay
to make it available for other calls.
BD, the No. 2' right front contact of relay CD, 35 In the preceding discussion the keying and
the No. 2 right front contact of relay AU, the No.
.registration of letters or digits having the'digit
2 right front contact of relay BU, the No. 3 right
values 1, 2, 3, 4, ;6,_ 7 and 0 have been described.
back contact of relay CU to conductor |330 and
If the digit 5 is keyed by the operation of key K5
thence over the No. 1 left contacts of an oper
thenan impulse of frequency a would be -sent
ated progress relay, similar to relay |401 but as 40 followed by an impulse of frequency b resulting
sociated with the hundreds digit register, to bat
in the operation of recording relays AD and BU.
tery through the winding of a relay of that regis
With these relays operated then when ground is
ter corresponding to relay |400 whereupon such
applied 'to the right armature of relay AD, a cir
relay operates and locks to register the hundreds
cuit is completed over the right front contact of
digit 0.
`
`
'
45 relay AD, the N0. 1 right back'contact of relay
With recording relays CD and AU operated to
BD, the No. 1 right back contact of.relay CD, the
record the receipt of signal impulses for the tens
No. 1 right back contact of relay AU, the No. 1
digit 6, then when ground is applied to the right
right‘front contact of relay BU, the No. 1 right
armature of relay AD a first circuit is completed
over the right back contact of relay AD, .the No. 2 50
right back contact of relay BD, the No. 2 right~
front contact of relay CD, the> No. 2 right front
contact of relay AU, No. 2 right back contact of
back contact of relay CU to conductor I 335 to
cause the operation of a relay of a, register, such _
as relay |405 of the first code digit register A.If the digit 8 is keyed by the operation of keyv
K8, then an impulse of frequency a is sent fol
relay BU, the No. 6 right back contact of relay
lowed by an impulse of frequency c resulting in
CU, conductor |33| and thence over the No. 2 55 the operation of recording relays AD and CU.
left contacts of an operated progress relay, simi
With these relays operated then when ground vis
lar to relay |401 but associated with the tens
applied to the right armature of relay ADa ñrst
digit register, to battery through th‘e winding of
circuit is completed over the right front contact
a relay of such register corresponding to relay
of relay AD, the No. 1 right back contact of relay
|40| whereupon such relay operates and locks. 60 BD, the No. 5 right back contact of relay CD, the
A second circuit is also established from ground
No. 5 right back contact of `relay AU, the No. 8
applied over the right back contact of relay AD,
right back contact of relay BU and the N o. 6 right
the No. 2 right back contact of relay BD, the No. 6
front contact of relay CU to conductor 133|; a
right front contact of relay CD, the No. 6 right
‘second circuit is completed over the right front
front contact of relay AU, the No. .4 right back 65 contact of relay AD, the No. l right back contact
contact of relay BU, the No. 1 right back contact
of relay BD, the No. 1 right back contact of relay
of relay CU, conductor |335 and thence over the
CD, the No. l right back contact of relay AU, the
No. 5 left contacts of an operated progress relay,
No. 1 right back contact of relay BU and the No.
similar to relay |401 but associated with the tens
`2 right front contact of relay CU to conductor
' digit register, to battery through the winding of
|332 and a, third circuit is established over the
a relay of that register corresponding to relay -70 right back contact of relay AD, the No. 1 right
|405 which thereupon operates and locks. With
back contact of relay BD, the No. `1 right back
these two register relays operated and the other
contact of relay CD, the No. 1 right back contact
relays of the tens digit register unoperated, the
of relay AU, the No. 1 right back contact of relay
tens digit 6 is registered.
75 BU and the No. 1 right iront contact of relay CU
asoaevs
i
i@
_to conductor |335. With ground applied to con
ductors |33|, |332 and |335- relays of. a digit reg
ister, such as relays |40i, |402, |405 of the iirst
code digit register A are operated to register the
digit
.
1
tively operating said reeds for causing the trans
mission of one impulse oi' a combination, timed
by said switch, during the down-stroke of a key >
and for selectively operating said 4reeds for caus
ing the transmission of the remaining impulse
of a combination, timed by said switch, during
If the digit 9 is keyed by the operation of key
the up-stroke of the operated key.
A,
K9, then an impulse of frequency b is sent fol
4. In a telephone system in which the selection
lowed by an impulse-of frequency c resulting in
of wanted lines is effected by transmitting over
the operation of recording relays BD and CU.
a line extending from a calling station impulse
With these relays operated, then when ground is
combinations made up of a plurality of fre
supplied to the right armature of relay AD, a
quencies within the‘voice frequency range, an
ñrst circuit is completed over the right back con
impulse generatorV at the calling station com
tact of> relay AD, the No. 3 right front contact of
prising a plurality 'of differently tuned preten
relay BD, the No. 3 right back contact ofV relay
CD, the No. 3 right back contact of relay AU, the 15 sioned reeds vibratable in an electromagnetic
field, a releasing member associated with each
No.5 right back contact of relay BU and the No.
of said reeds, a plurality of keys each having a
4 right front contact of relay CU to conductor
down-stroke and an up-stroke movement, a pair
|334 and a second circuit is established from'
of bars associated with each of said reed
ground over the right back contact of relay AD,
the No. 4 right front contact of relay BD, the No. 20 releasing members, means `controlled by the
operation of the ñrst bar of any pair for oper
4 right back contact of relay CD, the No. 4 right
ating the associated reed-releasing member.
back contact of relay AU, the No. 7 right back
means controlled by the release of the second bar
contact of relay BU and the No. '7 right front con
of any pair when operated for operating the as
tact of relay CU to conductor |335. With ground
applied to conductors |334 and |335, relays of 25 sociated reed~releasing Imember and means
controlled by said keys for selectively operating
a digit register such as relays |404 and |405 of the
and then releasing said bars to cause the
ñrst code digit register A are operated to register
selective operation of said reed-releasing mem
the digit 9.
bers, whereby one impulse of a combination is
What is claimed is:
1. In a telephone system in which the selection 30 transmitted during the down-stroke of a key and
the Aremaining impulse of a combination is
of wanted lines is eiîected by transmitting over
transmitted during the up-stroke of the operated
a line extending from a calling station impulse
key.
combinations made up of a, plurality of frequen
5. In a telephone _system in which the selection
cies within the voice-frequency range, an impulse
generator at the calling station comprising a plu 35 of wanted lines is effected by transmitting over
a line extending from a `calling station impulse
rality of diiîerently tuned reeds vibratable in an
combinations " of frequencies within the voice
electromagnetic field, a plurality of keys each
frequency range, an impulse generator at the
having a down-stroke and an up-stroke move
calling station comprising a plurality of difier
ment and means controlled by said keys 'for selec
tively operating said reeds for causing the trans-l 40 ently tuned pretensioned reeds vibratable in an
electromagnetic field, a release member asso
mission of one impulse of a combination during
ciated with each of said reeds, a plurality of
the down-stroke of a key and for selectively op
erating said reeds for causing the transmission of - keys each having a down-stroke and an- up
stroke movement, a pair of depressible bars as
theremaining impulse of a. combination during
45 sociated with each of said 'reed-releasing mem
the up-strcke of the operated key. bers, means controlled by the depression of the
2. In a telephone system in which the selection
first bar of any pair for operating the associated
of wanted lines is effected by transmitting .over a
reed-releasing member, means controlled by the
line extending from a calling station impulse com- l
releasing movement of the second bar-of any
binations made up of a plurality of frequencies
within the voice frequency range, an impulse gen 50 pair, if depressed, for operating the associated
reed-releasing member, and means controlled by
erator at the calling station comprising three
said lkeys for selectively depressing and then
differently tuned reeds vibratable in an electro
releasing said bars to cause the selective opera
magnetic iield, a plurality of keys each having a
tion of said reed-releasing members, whereby one
down-stroke and 'an up-stroke movement and
means controlled by said keys for selectively op 55 impulse of a combination is transmitted during
the down-stroke of a key and the remaining'
erating one of said reeds for causing the trans
impulse of a combination is transmitted during
mission of one impulse of a combination during
the up-stroke of the operated key.
the down-stroke of a key and for selectively oper
6. In a telephone system in which the selection _
ating one or two of said reeds for causing the
of wanted lines is eiîected by transmitting over
transmission of the remaining impulse of a com
bination during the up-stroke of the operated
a line extending 'from a calling station impulse
combinations of frequencies within the voice
key.
,
frequency range, an impulse generator at the
3. In a telephone system in which the selection
calling station comprising a plurality of difier
of wanted lines is eiîected by transmitting over a
line extending from said calling station impulse
ently tuned pretensioned reeds vibratable in an
combinations made up of a plurality of fre
electromagnetic `field, a releasing member asso
quencies within the voice frequency range, an im
cited with each of said reeds, a rotatable cam for
pulse generator at the calling station comprising
operating each releasing member.' a plurality of
keys each having a down-stroke and an up-stroke
a` plurality of differently tuned reeds vibratable
- , in an electromagnetic iield, a.plurality of keys 70 movement, a pair of depressible bars associated
with each of said cams, a ratchet assembly con
each having a down-stroke and an up-stroke
trolled by the depression of the ñrst bar of any
' movement, a timing switch momentarily operable
pair for rotating said cam to operate the asso
once during tlie‘down-stroke of an operated key
ciated reed-releasing member, a ratchet assembly
and again duringy the 11p-stroke of an operated
key. and means controlled by said keys for selec 75 controlled by the releasing movement oi the
l 2,403,475'
21
22
second bar'of any pair, it depressed, for rotating
said cams. a pair of depressible bars associated
with each pair o! ratchet assemblies. one of said
bars being eiïective upon its depression through
said cam to operate the associated reed-releasing>
mem-berand means associated with said keys for
selectively depressing -and then releasing said
bars to cause the selective operation of said reed
releaslng members, wherebyone impulse' of a
combination is transmitted during the down
stroke of a key and the remaining impulse of
the combination is transmitted during the up
stroke of the operated key.
7. In a telephone system in which the selec
tion of wanted lines is eiiected by transmitting
over a line extending from a calling station
impulse combinations of frequencies within the
one of said associated ratchet assemblies to
rotate the associated cam to operate the asso
ciated reed-releasing member and the other of
said bars being eiIective upon its releasing move
ment. if depressed'. through the other of the
associated ratchet assemblies to rotate the as
sociated cam to operate the associated reed
releasing member. a plurality of keys each having
a down-stroke and an up-stroke movement and
means associated with said keys for selectively
depressing and then releasing said bars to se
voice frequency range, an impulse generator at 16 lectively operate said reed-releasing members,
the calling station comprising a plurality oi' »
whereby one impulse of a combination is trans
mitted during the down-stroke of a key and the
diiïerently tuned pretensioned reeds vibratable »
remaining impulse of the combination is trans
in an electromagnetic held, a releasing member
mitted during the up-stroke of the operated key.
associated with each of said reeds, a rotatable
cam for operating each releasing member, a pair
l
HENRY M. BASCOM.
FRANCIS A. HUBBARD.
of ratchet assemblies associated with each of
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