US1303528A - Telephone-exchange system - Google Patents

Description

J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 23, VH6. RENEWED JAN. 9, 1919.

1,303,528. Patented May 13, 1919.,

TSHEETS-SHEET l.

J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION r1150 JUNE 23. 191.11. RENEWED m1.9.1919.

1,303,528. Patented May 13, 1919.

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IELEPHQNLEXCHANGE SYSTEM. APRLLCAHQNEHLRD. JUNE 23. 1916. RENEWED IAN. 9. 1919. 1,303,528. Patented May13, 1919,

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J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION mm mm: 2a.v 1915. RENEWED MN. 9. 1919.

Patented May 13,1919.

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J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION. man JUNE 23. ms. RENEWED JAN. 9. 1919.

1,303,528; Patented May 13, 1919.

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J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

Armcmuu. mun JLLNE 23..l91.6-.REWED JAN. 9. 1919.

Patented May 13, 191-9.

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TELEPHONE EXCHANGE SYSTEM. APPUCATION FILED JUNE 23.. 191-6.. ngugwgn JAN, 9, 1919.

. 1,303,528, Patented May 13, 1919.

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UNITED STATES PATENT OFFICE.

JOSEPH L. WRIGHT, OF CLEVELAND, OHIO, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Patented May 13, 1919.

Application filed June 23, 1916, Serial No. 105,334. Renewed January 9, 1919. Serial No. 270,436.

To all whom it may concern:

Be it known that I, JOSEPH L. WRIGHT, a citizen of the United States. residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification.

My invention relates to telephone, exchange systems, and especially co-systems of the semi-automatic type. p

In systems of this type the originated calls are automatically transferred to an idle operators position. The calls are thereafter extended by means of automatic switching mechanism to desired lines or trunks under control of the operator.

The switching mechanism under control of the operator comprises what are ordinarily termed first selector, second selector and connector switches. With my invention these switches are not driven predeterminedly in order to efl'ect the proper connections with lines or trunks. Each switch is entirely self-controlled by its own motive power. These switches in addition to being provided with. the usual movable wipers to engage cooperating contacts are provided with what may be termed designating wipers and contacts. These designating contacts are arranged in certaln' order and connected with corresponding contacts of the keyboards at each operators position.

Each operator is provided with a keyboard similar to that of an adding machine. Each key-boardis provided with a number of rows of keys or buttons each row consisting of ten buttons. The number of rows are determined by the number of switches in a series, under control of the operator to establish a connection from the line of the calling subscriber to the line of the called subscriber. One row of buttons is provided for each selector switch while two rows of buttons are provided for the connector switch of the series.

In the presentinstance I have shown my invention as applied to an exchange of tenthousand line capacity wherein first selector,

the button in the last row causes the keyboard to be automatically disconnected from the switches used in building up the con nection from the calling to the called subscribers line.

With this arrangement the progress of a call can be noted and any failure of a button to restore will indicate that a certain switch has not operated properly and the attendant in charge of the exchange can then quickly locate such a switch.

My invention is illustrated in the accom panying drawings wherein:

Figure 1 show-s a subscribers line and control circuit.

Fig. 2 shows a primary'and first selector switch circuit. I

Fig. 3 shows a second selector switch circuit.

Fig. 4 shows a connector switch circuit.

Fig; 5 shows a secondary or key-set switch control circuit.

common battery systems and the line wires from this station terminate at the central oiiice in a line relay 2. The line relays are d1v1ded into groups, there being ten groups to each one-hundred lines. The windings of each group of ten relays are common to the winding of a group relay 3' so that when any line relay is energized, the group relay associated with it is also energized. The

group relay when operated makes the row contact in the primary switch busy, while the line relay when operated makes the individual test contact in the primary switch busy.

The switch whenever a call is originated. In rotating this switch picks out an idle primary switch and starts the'same hunting for the calllng line.

W is common to a group of, one hundred lines and is made to rotate is similar to the primary switch. The spin-.

dle of this switch carries a set of row wipers which engage row contacts when the switch" is rotating and also another set of wipers which engage the vertical-rows of contacts after the switch finds the proper row con- .tact.

All of the primary, first selector and connector switches are provided with two distinct kinds of wipers, namely, row wipers to pick out the group while theswitch rotates and vertical wipers which pick out contacts in the vertical rows. The row wipers ,of the selector and connector switches in passing over the contacts cause certain cir- "cuit combinations in relation to the operators key-board or controlling device.

Referring again to Fig. 2, the wipers 63 of the prima switch 0 and the wipers 56 of the first se ector switch D are joined as indicated by the heavy lines for conversational purposes. The tip and sleeve conductors are separated by the condensers 43 and 44. Relay '23 and the retardation coil 26 supply talking current to the calling subscriber. Relay 21 is the starting relay of the primary switch and corresponds to the line relay 2 (Fig. 1), as it controls the action of the operators key-set switch (Fig.' 6 Relay 22 is the row test relay while 24 is the individual test relay. Rela 25 is operated when the key-set switch pic is out the trunk and "remains energized while the various switches are being controlled and until the connection between the calling and the called subscriber is established. Relay 27 is the test relay of the first selector switch and remains energized while the test wipers are passing over busy contacts. Relay 28 is energized whenever either the rotary or ver tical magnets of the primary switch are operated and also when the vertical and rotary magnets of the first selector switch are operated. The circuits of these magnets are normally completed through the back contacts of this relay 28, and so therefore whenever it is actuated the magnet circuits are broken. The action thus set up between the relay and the magnets cause the latter to vibrate and continue to do so until their energizing circuits are opened. I

The controlling relay 29 is connected to the row wiper in the manner shown.

When the row wiper engages the contact corresponding to the button depressed on the V key-board, the relay 29 is shunted and .in

restoring closes the circuit of the test relay 27. The relay 29 is energized in series with the resistance coil 42 at the initial operation of the switch D.

' Referring now to Fig. 3, the second selector switch at E is similar to that of the first selector switch andis controlled in the same manner. The control relay 84 is connected to the row wiper and when operated the circuit of the rotary magnet is disconnected and the vertical magnet connected in its place.

Referring now to Fig. 4, the connector switch at G is provided with a set of wipers 355 leading to the talking conductors of the called line and a test wiper 360 which is also a part of the circuit of the cut off relay.

Relay 310 is operated after the selection of the connector switch with which it is associated and closes the circuit of the rotary magnet causing the connector switch to rotate. Relay 310 is shunted after the proper row contact isselected and causes the operation of relay 315. This latter relay disconnects the rotary magnet and in its place connects the vertical magnet thereby causing the switch to step vertically.

When the proper individual designating contact is reached the relay 310 is again shunted and causes the operation of relay 320. This latter relay serves to disconnect the vertical magnet thereby causing the switch to come to rest with its wipers engaging contacts of the called for line.

Relay 345 is the test relay while 350 is the ringing relay controlled by the commutator 500.

Battery current is supplied to the line of the called subscriber through the windings of relay 335 and retardation coil 340.

Relay 305 is slow acting in restoring and serves to momentarily connect the test relay 345 to the test wipers 360.

Relay 330 serves to close the tip and sleeve conductors of the connector switch when it effects connection with a non-busy line. This relay 330 with relay 335 causes the initial action of ringing relay 350.

When the called subscriber answers he controls the action of the connector switch, while the calling subscriber controls the action of the primary, first and second selector switches.

Referring to Fig. 5, the switch shown at Y corresponds to the switch W of Fig. 1 and serves to pick out an idle secondary switch.

Referring to Fig. 6, the secondary switch is shown. The switch M is similar to and acts in the same manner as the primary switch C of Fig. 2. The wipers 167 connect with the tip and sleeve conductors of the prividualpalling primary trunk in the group.

Relay 156 is the signal relay and operates in series with relay 25 of Fig. 2. Relay 1.52 is the starting relay and corresponds to relay .21 and relay 153 is the row test relay. 15b

is the relay operated when the answering button 248 is depressed and serves to con nect the operators telephone set across the tip and sleeve conductors of the trunk. 157 is the starting relay and operated when the starting button 247 is depressed.

The operators key-board, shown in Fig. 7 comprises four rows of buttons, each row being equipped with ten buttons. These buttons are of the usual locking and indicating type and so arranged that when a button in a particular. row is depressed a common latch bar will be operated thereby releasing the button formerly depressed.

Each row of buttons of which thereare four is provided with a release magnet. These magnets serve to operate the common latch bar of its row when energized. These magnets designated as 721, 722, 723 and 724 are each controlled by their respective relays 711, 712, 713 and 714. Each one of these relays as shown is common to a particular row of buttons. Each row of buttons is also provided with a set of master contacts operated by the latch bar when a button in the row is depressed. The connections from these master springs of each row are in series relation. When a button in each of the four rows is depressed the connection eX- tending to the first row of buttons is connected to conductor 750. This conductor 750 is connected in proper sequence to the various rows of buttons R, S, T and U. The

connection to each row of buttons includes the winding of their respective relays 711, 712, 713 and 714.

The designating contacts of the selector and connector switches are connected in multiple, that is to say No. 1 contacts of each switch are connected in multiple, No. 2 contacts connected in multiple.

"With this arrangement combinations are setup between the keyboard and the switches whereby the latter are caused to come to rest on contacts corresponding to the buttons depressed on the key-board.

In case No. 1 button in the first row is depressed and the first selector switch which is controlled by the first row R is set in motion the circuit of relay 711 will be completed when the t lesignatingwiper of the first selector switch engages No. 1 designating contact such as 741. v

The operation of my system is asfollows:

The subscriber at A upon removing his receiver closes the circuit of the line relay 2 in series with the group relay 3. This latter relay operating closes the circuit of relay 4 which in turn connects ground to one terminal of the relay 5 and also closes the circuit of the stepping magnet 7. The step-ping magnet operating closes thecircuit of relay 6 which in turn opens the circuit of the magnet itself causing it to vibrate and step the switch W. This switch will continue to rotate until an idle primary switch such as shown in Fig. 2 is found. As soon as such a switch is found, the relay 5 is placed in series with relay 21 (Fig. 2) by the following path: ground, contact of relay 4, 5, 18, WV, 14, 21, 70, contact of relay 24 to battery B.

The relay 5 operating opens the circuit of the magnet '7 bringing the switch W to rest. Relay 21 operating closes the circuit of the rotary stepping magnet 31 by the following path: battery B, 80, back contact of relay magnet 31 causes the switch C to operate until the wiper 64 reaches the busy row contact.

The wiper 64 is carried on the same spindle with the wipers 63 and65, and while the switch is rotating the wiper 64 passes over contacts leading to the group relay 3. As there are ten of these group relays to each one-hundred lines it follows that the wiper 64 in rotating to its extreme position will pass over ten contacts.

There are ten sets of individual contacts arranged in vertical rows associated with each row contact and which the wipers 63 and 65 respectively engage. It follows therefore that after the switch picks out the group in which a line is calling, it will afterward step vertically until the wipers engage the contacts of the calling line.

As soon as the row contact is found, the circuit of relay 22 is closed as follows: battery B, 80, back contact of relay 24, 71,22, 64,

13, cont act of relay 3, to ground. The relay 22 in operating disconnects the rotary magnet 31 and in its place connects the vertical magnet 30, thereby causing the switch to step vertically until the busy individual test contact is found. As soon as such a. contact is found the circuit of relay 24 is closed as follows: battery B, 24, 68, contacts of relay 22, 67, 11, contacts of relay 2 to ground through the contacts of relay 1. Relay 24 operating opens the wire 71 and disconnects relay .22 which in falling back disconnects relay 24 from the wire 67 and connects it instead to Wire 66, thereby placing relays 24 and 1 in series.

The operating of relay 1 disconnects the line relay 2 and the group relay 3. Relay 24 connects battery to the windings of relays 23 and 25 and the falling back of relay 22 connects ground to the coil 26, thereby supplying the calling subscriber with talking current.

When such a switch is found as shown in series relay 21 and also relay 5 Relay 21 remains energized until the primary switch finds the calling line and until the key-set switch finds the trunk. Relay 21 when 'first actuated, places battery on the wire 79 to relay 130 and also places battery to wire 62 which is connected to the individual test contact of the key-set switch Relay 130 closes the circuit of the step-. ping magnet of the switch Y through the normally closed contacts. of relays 131, 132. The, magnet in operating closes the circuit of the interrupter relay 134, thereby causing the magnet to vibrate and the switch to rotate until an idle key-set switch is found.

Fig.6, relay 131 is placed in series with relay 152 by the following path: ground, contacts of relay 130, 131, 138, Y, 140, 152, 195, 196, 197, to battery B through the operators jack 400. Relay 131 operating places battery on wire 136 to relay 132. As soon as this latter relay operates ground is placed on the wire 138, thereby shunting relay 131. This direct ground placed on wire 138 makes the wire 140 which is multipled to other Y switches busy. The operating of relay 132 also places ground on the row wiper of the key-set switch by the following path: ground, 139, Y, 141, to the row contact.

The operation of relay 152 connects ground to the rotary magnet 165 through the back contact of relay 153 causing the switch M to rotate. This switch will rotate until the busy row contact is found, whereupon the circuit of! relay 153 will be closed as follows: battery B, contacts of relay 152,176, 153, 171, 168, 141, 139, contacts of relay 132 to ground. The key-set switch M operates in the same manner as the primary switch C (Fig. 2). Relay 153 disconnects the rotary magnet 165 and connects in its place the vertical magnet 164, thereby causing the switch to step vertically until the busy individual test contact is found.

' The finding of this contact closes the circuit 'of relay 154 as follows: ground, 154, 169, 62, 80, contacts of relay 21 to battery B. Relay 154 disconnects relay 152, thereby cutting off the vertical magnet and causing the key-set switch to rest on contacts leading to the calling primary trunk. Relay 152 becoming disengaged opens the circuitof relay 153 and this latter relay in falling back places relays 156 and '25 in by the following path: ground, back contact of relay 153, 175, back contact of relay 157, 202, contact of relay'1'55 winding of lay 156, 193, 169, 59, 25 to battery B through the contacts of relay 24. The operation of relay 25 (Fi 2) ,disconnects 'g. 1). The releasing of relay 5 frees the switch W allowing it to pick out other primary switches.

Relay 21 also releases relay 130, thereby restoring relay 132 so as to allow the switch Y to be used by other trunks in picking out key-set switches.

In the present system I have provided ten primary switches as shown in Fig. 2, for each one-hundred lines. Each group of ten primary switches is in turn provided with one Y switch for picking out idle key set switches. The percentage and grouping of the trunks and lines can be varied to suit tralrlc conditions.

Th wire 141 leading from the Y switch to the row contacts of the key-set switch is not multipled. The Y switch picks out an idle key-set switch and then places ground on the row contacts of the selected switch and these row contacts are not multipled. This arrangement prevents interference between other Y switches and also between the keyset switches. In no case is ground placed on more than one row contact ofany key-set switch at the same time.

In Fig. 1 the switch W is individual to one hundred lines and picks out a group of primary switches, and in this case the row contacts of a group of primary switches are multipled.

.The lighting of the lamp 243 notifies the operator of a call, and she then presses button 248 operating relay 155. The operationof this relay connects her telephone set across the trunk wires, disconnects relay 156, thereby extinguishing lamp 243. The disconnecting of relay 156 also opens the circuit of relay 25 (Fig. 2), which in falling back closes the tip and sleeve conductors of the trunk, allowing the operator to converse with the calling subscriber.

The operator upon receiving the number desired, which I will assume to be 147 0. sets up this number on the key-board in the following manner: She presses No. 1 button in the thousands row R, No. 4 button in the hundreds row S, No. 7 button in the tens row T and No. 10 button in the units row U. After setting up'these buttons she depresses the starting button 247 thereby completing the circuit of relay 157 b the following path: ground, contacts of button 247, 186, winding of relay 157, 193, 169, 59, winding of relay 25, contacts of relay 24 tobattery The operation of relay 157 disconnects relay 155 and connects the winding of relay 711,to the tip conductor 150 in series with the winding of relay 29 (Fig. 2) by the following path: ground, coil 701, winding of winding of relay 29, 36, cam 41, coil 42 to battery B. i

The operation of relay 711 completes the circuit of release magnet 721. The ener'-' gization of this magnet, however, does not operate the latch bar of the strip of buti 471, contacts of relay 27, contacts of relay 29, winding of magnet 34 to round. The operation of magnet 34- comp etes the c rcuit of relay 28 which in turn opens the cmcuit of the magnet itself. The vibration setup between the magnet 34 and the relay 28 causes the switch D to rotate.

At the first step of the switch the cam springs 41 through which relay 29 was initially energized are opened and relay 29 now has its circuit maintained to battery through its locking contact in series wit the resistance coil 42.

When the, wiper 48 engages the first contact 741 the circuits of relays 711 and 29 will be shunted.

It will be noted that the first contact 741 is connected to No. 1 button in the row R and as this button is now depressed current will flow over the conductor extending from contact 741 to button No. 1 in the row R as follows: round, resistance coil 701, contacts of No. 1 l autton in the row R, 741, 48, winding of resistance coil 42 to battery B. The current flows through this path just traced instead of through the path formerly traced which included the resistance of the windings of relays 711 and 29.

Relay 711 upon restoring causes the'deenergization of magnet 721 which upon restoring operates the latch bar and restores No. 1 button in the row R. The operation of the latch bar also restores the springs 731 to'the winding of relay 712 associated with the row of buttons S. This relay is, however, not operated at this time.

Relay 29 upon being shunted restores and completes the circuit of its relay 27 of the switch D by the following path: ground, cam springs 41, contacts of relay 29, cam springs 40, winding of relay 27, 45, contacts of relay 25 to battery B.

The operation of relay 27 and the restoration of relay 29 serve to disconnect the rotary magnet 34. The operation of relay 27, however, completes the circuit of'the vertical magnet 33 thereby causing the switch D to step vertically. Magnet 33 has its circuit interrupted by the relay 28. -After the switch D takes its first vertical step relay 27 is maintained energized by ground being connected to its locking contact by the test wiper 57.. passi over busy or grounded contacts. Ground 1s also supplied to the looking contact of relay 27 by the following path ground, cam springs 41, which were closed at the first rotary step of the switch D, 75, winding of release magnet 32,72, contacts of relay 28, 58, to the locking contact of relay 27. When the testwiper 57 engages a non-busy contact and when relay 28 is energized ground is entirely removed from the locking contact of relay 27 and it upon restoring opens the circuit of the vertical mgnet 33 causing the switch D to come to rest with its wipers engaging contacts leading to an idle second selector switch such as shown in Fig. 3.

As soon as the second selector switch is engaged relay 84 is placed in series with. the winding of relay 712 over the tip conductor in the same manner that relays 29 and 711 were connected. The operation of relay 84 completes the circuit of'the rotary magnet 87. This magnet in operating completes the circuit of relay 82 which in turn opens the circuit of the magnet itself. The vibration set up between the relay and the magnet causes the switch E to rotate.

At the firststep of-the switch E the cam springs are opened and the circuit of relay 84 is maintained locked to battery through its locking contact.

When the wiper 103 engages the fourth contact 744 which corresponds to the fourth button depressed in the row S relays 712 and 84 are shunted. The restoration of relay 84 completes the circuit of the test relay 83 which connects the vertical magnet 88 in place of the rotary magnet87. The rotary magnet 87 is disconnected by the joint action of relays 83 and 84. The restoration of relay 712 operates the,latch bar thereby restoring No. 4' button in the row S and also restores the springs 732 to normal posi tion. The restoration of these springs serve to connect relay 713 to conductor 750.

The switch Ewill continue to step vertically as long as the test relay 83 remains.

energized. This relay is deenergized as soon as the test wiper 102 engages a non-busy or ungrounded contact leading to an idle connector switch. Relay 82 also serves to maintain relay 83 energized while the switch E is stepping.

As soon as an idle connector switch is selected relays 713 and 310 are placed in series. The operation of relay 310 completes the circuit of the rotary magnet 395 of the switch by the following path: battery B, contacts of relay 310, 306, contacts of relay 315, 307, winding of magnet 390, 329, contacts of relay 685 to ground. The operation of magnet 390 completes the circuit of the vibrating relay 685 thereby interrupting the -tween the magnet switch G to rotate.

magnet circuit. The vibration set up and the relay causes the When the 'wiper 375 engagesli'o. 7 7 con- .tact, which corresponds to the depressed The shuntingof lay 310 completes the.

T, then relays 310 circuit of relay 315'by the followin path? battery B, contacts of relay 310, 311, cam

- springs 312, cam springs 314, winding of relay 315 to ground which is connected to the test. conductor 308 through the back contacts of relay 82 of Fig. 3. o

The operation of relay315 disconnects the rotary magnet 390 and in' its place connects the vertical magnet 395.

-- It will be noted that the relay 310 is only shunted momentarily for as soon as the latch bar of the row T is operated causing the springs 733 to assume their normal poi ing of relays 713 and the consequent delay sition, relay 310 is placed in series with the winding of relay 714. The time mterval, however, caused by the restoration or shunt? in placing relay 7.14 in series with relay 310 allows the latter relay to fully restore and operate relay 315. soon as relays 714 and'310 are placed in series the operation of .the latter relay completes the circuit of the vertical magnet 395 through the contacts of relay 315 thereby causing the switch G to step vertically. As soon as the wiper 365 engages the tenth contact connected to and corresponding to the depressed button No. 10 in the row U then relays 310 and 714 are shunted. 1."

The restoration of relay 310 completes the circuit of relay 320 by the following path battery B, 311, cam springs 312, cam springs 314', 318, winding of relay 320 to groundconnected" tothe test conductor through the contacts of relay 82. The operation of relay 320., disconnects the vert cal ,m et ;j3 9 5 thereby eausingthe' swans to come to rest with its wipers engaging contacts of the called-for line.

It will be noted that when relay 310 is ener 'zed the circuit of the slow acting relay 305 is completed. Relay 310 in restoring o ens the circuit of relay 305, but before t is latter relay fully restores test relay 345 is connected'to the test wiper 360 by the following path: ground, contacts of relay 82, test conductor 308, winding of relay .345, front contacts of relay 305, 342, back contacts of relay 310, 343 to the test wiper 360.

' In case the called-for line is busy, relay 345 1 then. relay 345 willnot be operated and re- .lay 355 will be placed. in 'series with the winding of the'cut-ofi relay of. the calledbyfreeing the operators controllingdevice will be operated and complete the circuit of the release magnet 385 thereby causing the restoration of the switch'G. The operation of relay 345 also serves to connect a suitable busy tone signal to the sleeve conductor 302 thus notifying the calling subscriber that the called-for line is busy. The operation ofrelay 345 also removes battery from winding of relay 355. This latter relay is connected to the test wiper 360'when relay 305 fully. restores. The removal of battery from its'winding in this manner prevents its operation in case the line is busy.

In case the called-for line is not busy,

for'line. Theoperation of relay 355 completes the circuit of relay 330 and the operation of this relay closes the'tip andsleeve conductors and connects battery and ground respectively to the retardation coil 340 and 'to'the winding of relay 355. The relay 335 and the retardation coil 340 serve to supply talking current to the called subscriber.

The operation of relay 355 completes the circuit of the ringing relay 350 by the following path: ground, commutator 500, winding ofrelay 350, contacts of relay 355, 337, contacts of relay 320 to battery B. The relay 350 under influence of the commutator 500 connects generator current 356 intermittently to the line of the called subscriber. f The operation of relay 330 disconnects the winding of relay 310 from the tip conductor so as to prevent the further operation of relay 310.

When the. called subscriber answers relay 335 is energized and the operation of this relay removes battery from the locking contactsof relays 315 and 320 thereby causing their restoration. The restoration of relay 320 opens the circuit of the ringing relay 350 thereby preventing its further operation. The operation of relay 335 also connects ground to the test conductor 308 thereby rendering connector switch G busy against incoming calls.

When relay 714 (Fig. 7) is shunted it causes the deenergization of magnet 724 ing the restoration "of No. 10 button in the row U. The restoration of the latch bar causes the cam springs 734 to assume their normal position. The restoration of relay 714 also removes .ground from'the winding of the release magnet 166 of the switch M. This magnet. upon becoming deenergized causes the restoration of the switch M therefrom a primary trunk;

After the parties are through talking the called subscriber upon replacing his receiver causes-relay 335 to restore, thereby completing the circuit of the release magnet 385 by the following path: battery B, contacts of relay 310, 321, contacts of relay 335, 322,

contacts of relay 315, winding of magnet 385, 331, cam springs 397, to ground. The action of the release magnet restores the switch G to its normal position.

The calling subscriber upon hanging up the resistance coils in series instead of pass mg through the windings of the control relays.

his receiver causes the tip relay 23 (Fig. 2) i to fall back, thereby closing the circuit of the release magnet 32 as follows: battery B,

cam springs 38, 73, contacts of relay 2'3, 58, contacts of relay 28, 72, 32, 75, cam springs 41 to ground. The operation of this magcontacts of relay 23, 58, contacts of relay 28, 72, 32, to ground through the cam springs 41. The operation of magnet 35 restores the switch D, thereby opening the cam springs 41 and disconnecting the energizing circuit for the release magnets. As soon as the test wiper 57 ofthe first selector switch leaves the test contact, then the relay 81 (Fig. 3) falls back and closes the circuit of the release magnet 86 as follows: battery B. contacts of relay 81, 86, 89, cam springs 95 to ground. The operation of this magnet causes the switch E to restore and open the release circuit.

In case the called party does not answer, then the calling party has complete control of all the switches and releases the primary, first and second selectors in the manner just described. The releasing of the second selector or switch (Fig. 3) removes ground from the test wire 308, disconnects all the relays 315 and 320, thereby closing the circuit of the release magnet 385 just as though the called subscriber had answeredand then hung up his receiver.

From the foregoing description it will be seen that the various switches are placed in operation over a control conductor extending from the key-board to the switches. This control conductor or'starting circuit embraces the windings of the control relays or the switches and key-board which are placed in series in a certain order. This control circuit also includes a resistance coil in.

depressedbutton places that'cond'u'ctor in multiple with the control conductor.

The conductor connected to the designating contact affords a path of low resistance for current to flow through the windings of Having thus described my invention what I desire'to secure by Letters Patent is:

1. .In a telephone exchange system, the combination with an automatic switch provided with a relay, stepping means for said switch, means for energizing said relay for rendering operable said stepping means, means controlled by said switch when it assumes a predetermined position to shunt said relay thereby disabling said stepping means.

2. In a telephone exchange system, the combination with an automatic switch. having associated contacts, a keyboard provided 'with a plurality of depressible buttons, a

relay, means for energizing said relay for placing said switch in action, means controlled through the contactsof said switch for shunting said relay and thereby arresting the action of said switch when it assumes a position corresponding to a depressed button on said key-board.

3. Ina telephone exchange system, the combination with an automatic switch, of a key-board containing a set of depressible buttons, a conductor extending between said switch and key-board, a relay associated with said switch, means for energizing said relay over said conductor to cause the operation of said switch, means for shunting said relay for disabling said switch when it assumes a position corresponding to the depressed button on said key-board. 4

t. In a telephone exchange system, the combinationwith an automatic switchprovided with designating contacts, of a keyboard comprising a set of depressible buttons equal in number to thenumber of designating contacts, a conductor common to and extending from said key-board to said switch, a conductor extending from each of said contacts to a particular button of the set, a relay, means for energizing said relay over said common conductor to actuate said switch, means controlled over one of said other conductors when the switch engages a contact corresponding to the depressed button to shunt said relay and disable said actuating means.

5. In a telephone exchange system, the combination with an automatic switch provided with designating contacts, of a keyboard comprising a set of depressible buttons, a conductor extending from each of said contacts to a particular button of the set, a relay, means for energizing said relay 1 Ypressed buttonto shunt said relay anddisable said actuating means. I

6. In a telephone exchange system, the

combination with an automatic switch having. primary and secondary action, desi nating contacts associated with said switc a key-board comprising a set of depressible buttons, each of said buttons allotted to a certain of said designating contacts, a relay,

' means for energizmg said relay tocause the primary action of said switch, means controlled over one of said contacts when the switch assumes a position corresponding to the depressed button to shunt said relay whereby said primary action of the switch v is disabled-and the secondary action started.

' maryaction and to start the secondary ac- I tion of said switch. 8. In a telephone exchange system, th

- combination with a two-direction automatic switch-provided with. designating contacts, of a key-board comprising a set of depressible buttons, each of said buttons being allotted to a certain one of said contacts, a control relay, and: a test relay associated with said switch, means for energizing said control relay to operate said switch in one 'direction,.means for shunting said control relay when the switch assumes a position corresponding to the depressed button of said set, the shunting of said relay serving to actuate said test relay to cause-the automatic operation of said switch in another direction.

9. In a, telephone exchange system, the combinationwith an automatic switch having associated contacts, arelay associated with said switch, a key-board provided with a plurality of depressible buttons, a relay associated with said key-board, means for energizing bothof said relays in series, the first of said relays when energized serving to place said switch in action and the second of'said relays when energized serving to place said key-board in association with said switch, restoring means for said key-board, means controlled through, the contacts of said switch for shunting both of said relays, the shunting of the first of said relays serving to arrest the action of said switch and the shunting ofthe second of said relays serving to operate said restoring means and disconnect said key-board from said switch.

10. In a telephone exchange system, the combination with an automatic switch provided with a control relay, of a key-board containing a set of depressible buttonsand provided with a control relay, a c

"serving to operate the restoring said key-board.

11. In a telephone exchange combination with an automatic key-board containing a set oi buttons, a conductor extending T switch and said key-board, saihaving an appreciable amount means exercised over said con. causing the operation" of said svc rality of other conductors extea said switch having less rcsistam first mentioned conductor, mear by said switch in its Operation any one of the second mentions. ductors in multiple with the firs conductor, the placing of one o ductors in multiple with the fin conductor serving to arrest the aswitch.

'12. In a telephone exchange combination with an automatic vided with a set of contacts, a ciated with said switch, a cont;- extending to said switch lea-vi) ciable amount of resistance, me: gizing said relay over said c1: placing said switch in opera-ti; designatin conductors ester, contacts 0 said switch, means said switch in its 0 eration to p of saidconductors 1n multiple trol conductor, any one of saii conductors when placed in i said control conductor servimr. 1 relay and arrest the operationlei 13. In a telephone exchanp; combination with an autos": vided with contacts, a contra-A? tending to said switch having; amount of resistance, means 1 said switch over said conduct-1 trolled by said switch in its or engaging said contacts to Shin circuit and arrest the ope a switch.

14. In a telephone exchai combination of an automatF-.

plng means for said SWlik causing the operation of sair means controlled by said a sumes a predetermined posit I dering operable said operating means, means. .15

switchin assuming the designated circuit thereby disabling said stepping means. c

15. In a telephone exchange system, the combination of an automatic switch, operoperating meansk I 16. In a telephone exchange system, the

combination of anautomatic switch, operat-' ing means for said switch, a circuit for renfor desi atm' E the position to beassumed by said s witc means controlled by paid 1 1011 I for shunting said circuit thereby disabling said operating means.

f 17. In a telephone exchange system, the combination of an automatic switch havm associated contacts, a key-board provid with a'plurality of depressible buttons, op-

- crating means for said switch, a circuit for rendenng o erable said operating means for placing sai switch 1n actlon, means controlled through the contacts of said switch for shunting said circuit and thereby arrest-.

ing the action of said switch when it assumes .a position corresponding to the depremed button on said key-board.

18. In a telephone exchange system, the

Loombination of an automatic switch, a keyboard containing a set of de ressible buttons, a conductor extending etween said switch and-said key-board, operating means i for said switch, means for rendering operfor said switch, means for rendering able said operating means over sald con ductor to cause the action of said switch, means for shunting said operating means for disabling said switch when it assumes a position corresponding to the depressed button on said key-board,

19. In a tele hone exchange system, the combinationo an automatic switch provided withdesignating contacts, of a keyboard comprising a set of depressible buttons equal 1n number to the number of deslgnating contacts, a conductor extending from said key-board to said switch, a "conductor extending from each of said contacts to a particular button of the set, actuating means operable said:actuating means over sald conductor extending between said switch and key-board, means controlled over one of said other conductors when the switch engages a contact corresponding to the depressed button to shunt said operating means todisable the actuating means for said switch.

20. In a telephone exchange system, the

combination of an automatic switch having primary and secondary action, designating contacts associated with said switch, a key- .21. In a tele hone combination 0F a switches provided wlth designating contacts, means for operating said switches, a keyboard comprising a set of depressible buttons, said buttons being multipled to correboardcomprising a set of depressible buttons; each of said buttons being allotted to a certain one of said designating contacts,-

means for causing theprimary action of said switch, means controlled over one of said contacts when the switch assumes a posltion corresponding to the depressed button to shunt the means for .causing the primary action of said switch, theshunting of said means serving to cause the secondary action of said switch.

exchange system, the

lurality of automatic spo'nding contacts of said switches, means for controlling the action of said switches over said contacts according to the depressed buttons. I

22. Ina telephone exchange system, the combination of an automatic switch having associated contacts, a key-board provided with a plurality of depressible buttons, a relayassociated with said key-board, means for energizing said relay, restoring means for said key-board, means controlled through the contacts of said switch for shunting said i relay, the shunting of said relay serving to operate said restoring means.

23. In a telephone exchange system, the combination of an automatic switch, of a key-board provided with a plurality of depressible buttons and having an associated control relay, a conductor extending between said switch and said key-board, means for energizing said relay over said conductor, restoring means for said key-board, means for shunting said relay when the switchassumes a position corresponding to the depressed button on said key-board, the shunting of said relay serving to operate the restoring means for said key-board.

24. In a telephone exchange system, the

combination of an automatic switch, of a key-board containing a set of depressible buttons, a conductor extending between said switch and said key-board, means exercised over said conductor for causing the operation of said switch, a plurality of other conductors extending from said switch tosaid key-board, means controlled by said switch in its'operation for. placing any oneof the second mentioned set of conductors in multilple with the first mentioned conductor, the p acing of these conductors in multiple servmg to arrest the action of said switch.

25. In a telephone exchange system, the combination of an automatic switch provided with a set of contacts, a control conductor extending to said switch, means for causing the operation of said switch over said control conductor, a conductor assothe operation of saidswltch.

t if j "1,303,523

ciated With'each of said contacts, means con- In testimony whereof I ei iix my signature trolled by' said switch inits. operationto in the presence of two witnesses.

' JOSEPH L. WRIGHT. Witnesses:

H. POLATSEK, A. M CUNE.

' place any one of said conductors in multiple with 'said control conductor, the placing of. 5 these conductors in multiple serving to arrest

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