US1205499A - Telephone-exchange system. - Google Patents

Description

i. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB-8. 1912.

1,205,499. I Patnted Nov. 21, 1916.

1 SHEETS-SHEET I.

J. L. WRIGHT.

Patented Nov. 21, 1916.

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J. L. WRIGHT. TELEPHONE EXCJHAN'GE SYSTEM. JAPPLICATION FILED FEB. 8, 1912.

Patented Nov. 21, 1916.

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J, L. WRIGHT. IELEPHONE EXCHANGE SYSTEM.

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J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. 8. m2.

1,205,499. Patented-Nov. 21,1916.

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.I. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. B, 1912.

UNITED STATES PATENT ornron.

JOSEPH L. WRIGHT, OF VVASH-INGTON, DISTRICT OF COLUMBIA, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 JAMES R. GARFIELD, TRUSTEE, OF CLEVELAND, OHIO.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Nov. 21, 1916.

Application filed February 8, 1912. Serial No. 676,395.

To all whom it may concern:

Be it known that I, Josnrrr L. .IVRIGHT, a citizen of the United States, and resident of Washington, District of Columbia, 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 has for its object the provision of an improved means in recording or indicating calls between exchanges or switching stations.

In trunking between exchanges, I use what I term indicating trunks as they terminate at one end in indicators or number wheels associated with plugs, jacks or other connecting means. These indicators are located before a B or trunking operator and are controlled by an A operator, who first receives the call.

The A operator is provided with a suitable sending device and upon receiving a call for another exchange, manipulates her sending device, causing the indicators to register the'number of the desired line.

The indicators have associated signal lamps which notify the B operator the condition of the connection.

Another feature of my invention consists in providing a selective ringing device, associated with the indicators and also controlled by the A operator. This device, instead of operating a number wheel, actuates sets of contact springs by suitable cam arrangements.

In the present case, I have shown the indicators and ringing devices associated with trunks terminating in plugs and cords before the B operator. The ringing is automatic, and the duties of the B operator are reduced to a minimum, as she merely picks up the plug associated with the inclicator and places it into the jack of the desired line.

In the accompanying drawings, I have" from manual to manual exchanges or from a full automatic to a manual exchange.

My invention is illustrated in the accompanying drawings, wherein:

Figure 1 shows a line and control circuit. Fig. 2 shows primary and first selector switch circuits. Fig. 3 shows an indicating trunk at a manual exchange. Fig. t shows a subs cribers line circuit at a manual exchange. Fig 5 shows the key-set control circuit. Fig. 6 shows an operators key-set switch'circuit. Fig. 7 shows an operators keyboard and sending device.

Referring now to Fig.1,the subscribers station is equipped with apparatus usual in common battery systems. The line wires from the subscribers station terminate in the central oflicein the line relay 2. The line relays are divided into groups, there being ten groups to each one hundred lines. Each group of ten line relays is common to one group relay 3. The group relay, when actuated, makes the row contact in the primary. switch busy, while the line relay, when actuated, makes the individual contact in the primary selector switch'busy. The

switch W starts to rotate whenever the group relay is energized, and continues to rotate until an idle primary switch is picked out. I Vhen such an idle primary switch is picked out, it first starts to rotate until the row wiper picks out the busy row contact and after reaching this contact it ceases to rotate and steps vertically until the individual busy test contact is found.

Referring now,to Fig. 2, the primary switch C is shown, which picks out the calling line. The first selector switch is shown at D, which responds to impulses from the sending device and picks out an idle indicating trunk leading to a manual exchange. Wipers 63 of the primary switchC and wipers 56 of the first selector 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 4%. Through relay 23 and the retardation coil 26 talking current is supplied to the calling subscriber. vRelay 21 is the starting relay for the primary switch, and

also corresponds to the line relay (Fig. 1) in that it controls the action of the operators key-set switch (Fig. 6). Relay 22 is the row test relay, while 25! is the individual test relay. Relay 25 is operated when the key-set switch picks out the trunk, and remains energized while the impulses are being transmitted, thereby opening the trunk conductors. Relay 27 is the test relay used in connection with the first selector switch for picking out an idle trunk. Relay 28 is energized whenever either the rotary or vertical magnets of the primary switch are operated and also when the vertical magnet of the first selector switch is operated. The circuits of these magnets are normally completed through the back contacts of this relay 28 and so, therefore, when it is actuated the magnet circuits are opened. The action of this relay and the magnets cause the latter to vibrate and to continue to do so until the energizing circuit is opened.

Referring now to Fig. 3, the indicating trunk consists of the number wheels controlled by their stepping magnets, shown at H, I, J. The selective ringing device is shown at K in its normal or resting position. At the first step of the magnet 102, the cam 100 closes the springs 103 and 102k, thereby connecting number 1 generator to the contact of the ringing relay 95. At the second step, the contacts 10% and 103 are broken and contacts 106 and 107 are closed by the cam 101. At the third step, the springs 103 and 105 are closed by the cam 100, and the springs 106 and 107 are then opened by the cam 101. At the fourth step, he springs 107 and 108 are closed by the cam 101, while springs 103 and 105 are opened by the cam 100. From the foregoing, it will be seen that the generators are cut on in regularorder corresponding to the number of impulses transmitted. The number wheels or indicators and the selective ringing device are cut on in proper order by means of the shifting switch shown at X. This switch is controlled and made to step forward one step by the action of the repeating relay 81. This latter relay responds to impulses from the sending device. Relay 98 also responds to impulses from the sending device and operates the various number wheels and the selective ringing device in proper order through the contacts of the switch X' The tip and sleeve conductors from the semiautomatic exchange lead to a two conductor plug, shown at PP. These conductors are separated by means of thecondensers 91 and 92, and the repeating coil 93. Through the relays 83 and 8% talking current is supplied to the called subscribers line. The ringing relay 95 is controlled by the commutator 90. The lamp S7 is lighted when the indicators have been operated and notifies the B optrunk.

erator of the call. The supervisory lamp 86 notifies the operator when the called subscriber answers. Relay S5 is actuated by the relay 83 when the called subscriber answers, and prevents any further action of the ringing relay.

Fig. a shows a subscribers line circuit in the manual exchange, and is very similar to that shown in Fig. 1, the main difference being that it is what is commonly known as a two wire circuit.

Referring now to Fig. 5, the switch Y acts in the same manner as the switch (Fig. 1) but instead of picking out a primary switch, it picks out an idle operators keyet switch.

Referring to Figs. 6 and 7, the key-set switch is shown at M. The wipers 167 connect to the tip and sleeve sides of the first selector in Fig. 2, over which the operator converses with the calling subscriber and over which the impulses are transmitted. 168 is the row wiper and picks out the group of ten in which the calling trunk is located. Relay 15 1 is connected to the individual test viper, which picks out the particular trunk in the group calling. Relay 156 is the signal relay and pulls up in series with relay 25 (Fig. 2) when the trunk is picked out, and when energized closes the circuits of the two lamps 2st?) and 2st (Fig. 7 notifying the operator. of a call. 152 is the starting relay and corresponds to relay 21 (Fig. 2) while 153 is the row test relay. Relay 155 responds when the operator presses the answering button 24:8, thereby connecting her telephone-set across the tip and sleeve conductors of the trunk. 157 is actuated when the operator presses Relay 7 the starting button 247. The action of this relay disconnects relay 155 and connects the starting wire controlled by the cam 231 to the stepping magnet 161, thereby causing the switch arms to step over the banks N, O, P. This stepping magnet is operated once at each rotation of the sending device and cuts on the impulses from the keyboard (Fig. 7) in regular order. The order in which these impulses are transmitted is as follows: At the first rotation of the sending device, the impulses corresponding to the thousands are sent over the tip side of the trunk. t the second rotation, a single test impulse is sent over the sleeve side of the At the third rotation, impulses corresponding to the hundreds are sent over the tip side of the trunk, and at the fourth rotation, a single test impulse is sent over the sleeve side of the trunk, etc. The order in which these impulses are sent is uniform,'

there being a single test impulse interposed between each set of the numeral impulses. After the last impulse has been sent, the

wiper passing over the bank of contacts P,

closes the circuit of relay 158, causing the switch to rapidly rotate until it reaches its normal position. normal position, however, the Circuit of the release magnet 166, of the key-set switch M, is energized, thereby releasing this switch and preventing the operator listening in or interfering with a connection. Relay 163 corresponds to relay 28, (Fig. 2), and causes the magnets 164 and 165 to vibrate until their energizing circuits are opened.

The operators keyboard, shown in Fig. 7 consists of five rows of buttons each row having ten buttons. Number 1 button of each row is connected to a contact operated by the cam 232. Number 2 button of each row is connected to the contact operated by the cam 233. Corresponding buttons ineach row are connected to the same contact. The contact controlled by the cam 232 is closed just long enough to keep the relay 160 (Fig. 6) energized while one impulse is being transmitted by the impulse wheel 242. If Number 10 button were down, relay 160 would be closed by the cam 241 just long enough for ten impulses to be transmitted by the impulse wheel 242. The contacts of the impulse wheel 242 are connected directly to the normally open contact of relay 160, and when this relay is energized, the impulses are connected to either the tip or sleeve side of the trunk, depending upon the position of the arm in regard to the contacts of the bank N. The buttons or keys shown in these five rows in Fig. 7, are of the usual locking and indicating type. When any one button of a certain row is depressed, it will release the button formerly depressed.

The buttons 246, 247 and 248 are of the non-locking type and the contacts controlled by them are only closed while the operator is ressing the button.

Other points in connection with the various figures will be brought out in the detailed description of the operation.

The operation of my system is as follows: The subscriber A, upon removing his receiver closes the circuit of the line relay 2 in series with the group relay 3. The relay 3 operating closes the circuit, of the 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 stepping magnet 7 operating closes the circuit of relay 6, which in turn opens the circuit of magnet 7, causing it to vibrate and step around the wiper of the switch This switch will continue to: rotate until the wiper finds an idle primary switch, such as shown at C Fig". 2. As soon as such an idle switch is found. relay 5 is placed in series with relay 21 (Fig. 2) by the followingpath: ground, contact of relay 4, 5, 18, 7, 14, 21, 70, contact of relay 24 to battery.

Just before reaching its The relay 5 becoming energized, opens the circuit of the stepping magnet 7, bringing the switch V to rest. Relay 21 operating closes the circuit of the rotary stepping magnet 31 by th following path: battery B, 80, back contact of relay 24, 71, contact of relay 28, back contact of relay 22, 31 to ground. The operation of magnet 31 causes the primary switch C to rotate until the wiper 64 reaches the busy contact connected to the wire 13. The wiper 64 is carried on the same spindle with wipers 63 and 65. 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 can come into engagement with any one of ten contacts.

There are ten sets of individual contacts arranged in vertical rows, associated with each row contact which the wipers 63 and 65 respectively engage. It therefore follows 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 13, 80, 71, 22, 64, 13, contact of relay 3 to ground. nects 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 the latter contact is found, the relay 24 is energized by the following path: battery 13, 24, 68,-contacts of relay 22, 67, 11, contacts of relay 2 to ground through the contacts of relay 1. The relay 24 operat- The relay 22 operating, disconing opens the wire 71 and disconnects relay 22. Relay 22, in falling back, disconnects relay 24 from wire 67 and connects it instead to wire 66, thereby placing the relay 24 in series with relay 1. The operating of relay 1 now disconnects the line relay 2 and also the group relay 3. The operating of relay 24 connects battery to the windings of relays 23, and 25 and the falling back of relay 22 connects ground to the retardation coil 26, thereby supplying the calling subseriber with talking battery. The relay 21 remains energized until the primary switch finds the calling line, and until the key-set switch finds the trunk. The relay 21 when first actuated placed battery on the wire 79 to relay 130, to ground, and also placed battery to wire 62 leading to individual test contact of th key-set switch (Fig. 6). The relay 130 operating closes the circuit'of the stepping magnet 133 of the switch Y through the normally closed contacts of relays 131 and 132. The switch magnet in operating closes the circuit of the inter rupter relay 134, which causes a Vibrating effect between the magnet and the relay 134.

The switch will continue to rotate until the idle key-set switch is found. As soon as such a switch is found as shown in Fig. 6, relay 131 is placed in series with relay 152, (Fig. 6), by the following path: ground, contacts of relay 130, 131, 138. Y, 140, 152, 195', 196, 197 to battery through the operators jack.

Relay 131 operating places battery on wire 136 to relay 132, causing it to operate. As soon as this relay operates, it places ground on 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 rey-set switch by the following path: ground, 139, Y, 141 to the row contact.

Relay 152 operating places ground on the rotary magnet 165 through the back contact of relay 153, thereby causing the switch M to rotate. The switch will continue to rotate until the busy row cont-act is found, whereupon the circuit of the relay 153 will be closed by the following path: battery 13, 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 selector switch C (Fig. The operating of relay 153 disconnects the rotary magnet 165 and in its place connects the vertical magnet 164, thereby causing the key-set switch to step vertically until the busy individual test contact is found. As soon as this contact is found, the circuit of relay 154 is closed by the following path: ground, 154, 172, 62, 80, contacts of relay 21 to battery B. The operating of relay 154 disconnects relay 152, thereby cutting 02 the vertical magnet, causing the key-set switch to rest on contacts leading to the calling primary trunk. Relay 152 becoming disconnected, opens circuit of relay l53 and this latter relay in falling back places the relays 156 and 25 in series by the following path: ground, back contact of relay 153, 175, back contact of relay 157, 202, back contact of relay 155, 156, 193, contacts of relay 158, 170, 59, 25 to battery B through the contacts of relay 24.

The operating of relay 25 (Fig. 2) disconnects relay 21 and relay 5 (Fig. 1). The releasing of relay 5 frees the switch WV, allowing it to pick out other primary switches. Relay 156 operating places battery on wires 181 and 183, thereby causing the lamps 243, and 244 (Fig. 7 to light. As soon as relay 21 in Fig. 2, became disconnected battery was removed from the individual test contact of the key-set switch,

allowing relay 154 to fall back. The fall- 'ing back of relay 21 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 100 lines. Each group of ten primary switches, as in Fig. 2, is provided with one Y switch which picks out an idle key-set switch. The wire 141, leading from the Y switch to the row contact of the keyset switch, is multipled. As soon as the Y switch picks out a key-set switch, ground is placed on the row contact of the selected switch. This prevents interference in case other Y switches, associated with other trunks, are picking out other switches. In no case is ground placed on more than one row contact of any key-set switch at the same time. This method allows calls to come from different groups of trunks at the same time, and yet prevents interference between key-set switches.

In Fig. 1, the W switch is individual to one hundred lines and picks out a group of primary switches and in this case the row contacts of a group are multipled, as only one primary switch at a time is started in search of the calling line. The percentage and grouping of the primary switches can be increased or decreased to suit traffic conkey-set ditions. The lighting of the two lamps 243,

and 244 notifies the operator of a call and she then presses the button 248 operating relay 155, thereby connecting her telephone set across the tip and sleeve conductors of the trunk. The operating of relay 155 disconnects relay 156, thereby extinguishing lamps 243, and 244, but at the same time lamp 245 is lighted. Relay 156 being disconnected allows relay 25 (Fig. 2) to fall back, closing the tip and sleeve conductors of the trunk, allowing the operator to converse with the calling subscriber.

If the calling party desired to converse with some one in the semi-automatic exsired to converse with some one in the semiautomatic exchange, the first selector switch D (Fig. 2) would rotate until the wipers came to rest in line with contacts leading to second selector switches, and then automatically pick out an idle one. After the second selector switch was picked out, it would change, the operator would set up the proper in turn pick out an idle connector which would pick out the line of the called party in the regular manner.

I have not shown second selectors or connector switches, as they form no part of the present invention.

If the calling party wishes to converse with a party in a manual exchange, the operator sets up on her key-board first the number or location of the exchange which would be represented in the row of buttons R. She would then set up a button in the row S corresponding to the hundreds, a button in the row T corresponding to the tens, a button in the row U corresponding to the units, and finally a button in the row V corresponding to the party line, letter or numher.

In the present instance, I have shown the manual exchange to be of one thousand lines capacity, and in case of a larger exchange, it would only be necessary to add additional rows of buttons to the operators key-set and additional indicators or number wheels before the operators at the manual exchange.

Ten buttons are shown in the row V, but the selective ringing device in Fig. 3 is only arranged to select any one of four kinds of ringing current. The cams of this same device, however, could readily be arranged so as to perform any method of party line ringing. The operator, after getting the proper number at the manual exchange, and pressing the corresponding buttons, then presses the button 247. This button closes the circuit of the starting relay 157, by the following path: ground 247, 186, 157, 193, 170, wiper 169, 59, 25, to battery B throughthe contacts of relay 24. The relay 25 again operating, opens the trunk conductors and prevents the calling party from hearing the impulses. The operating of relay 157 disconnects the relay 155, extinguishing lamp and causing the guard lamp 244 to light. Relay 157 also connects the starting wire 189, to contacts operated by the cam 231, to the stepping magnet 161. As soon as the contact springs are operated by the cam 231, the wipers of the shifting switch take one step and connect the impulse wire 191 to the tip side of the trunk 150 through the contacts of relay 160. v

i If the trunks leading to the manual exchange are in the tenth row of contacts in the first selector switch (Fig. 2) and the operator has pressed No. 10 button in the row R, the relay 160 will be held energized by the operation of the cam 241 until ten impulses have been transmitted by the commutator 242. These impulses operate the rotary relay 29 (Fig. 2) by the following path: ground, 242, 191, 190, 192, contacts of relay 160, 198, N, 150, 167, 60, 54, 29, cam springs 40 to battery B. The relay 29 responding to these impulses, closes the circuit of the rotary magnet 34, causing the first selector switch D to rotate and come opposite a group of trunks leading to the manual exchange. After these rotary impulses have been sent, the starting cam 231 causes the shifting switch to take another step, thereby connecting the wire 198 to the sleeve side of the trunk 151. The relay 160 now receives a single test impulse caused by the action of the cam 230. This impulse operates the relay 27 (Fig. 2) by the following path: ground, 242, 191, 190, 192, contacts of relay 160, 198, N, 151, 167, 61, relay 27, cam springs 40 to battery B. The relay 27, receiving this impulse, is held energized by the following path: battery B, contacts of relay 25, locking contacts of relay 27, 58, contacts of relay-28, 72 to ground through cam springs 41, as these latter cam springs were operated when the switch took its first rotary motion. The operating of this relay 27 closes the circuit of the vertical magnet 33 by the following path: battery B, contacts of relay 28, 71, contacts of relay 27, 33, to ground. The magnet 33 in operating, closes the circuit of'the relay 28, which in turn opens-the circuit of the magnet 33 itself. The action of this relay and magnet causes the latter to vibrate, stepping the switch D vertically. hen the circuit of the relay 28 is closed by the action of the magnet 33,'the relay-27 has its circuit partially opened, but it will remain energized by the test wiper 57 in passingover ground or busy contacts. If, while the magnet 28 is operated, the wiper 57 comes to rest on an idle contact, the relay 27 will at once become deenergized and disconnect the vertical magnet 33. As soon as the switch D takes its first vertical step, or while it is in the act of taking this step, the cam springs 40 are opened, thereby disconnecting relays 27 and 29 respectively from the tip and sleeve sides of the trunk. The relays 36 connected to test contacts leading to the manual exchanges, are of a high resistance, so as not to render the contacts to which they are connected busy. After the test wiper 57 picks out an idle trunk, the subscriber is connected to the manual exchange.

At the third rotation of the sending device, impulses corresponding to the hundreds are sent over the tip side of the trunk to the manual exchange operating relay 98. This relay closes the circuit of the indicating magnet 284 by the following path: battery B, contacts of relay 98, 123, E, 260, 284 to ground. This indicator magnet operating causes a suitable number wheel to register the proper number. The indicators used are of the type commonly known as Veeder counters. The relay 98 operating closes the circuit of the locking or control relay 82. This latter relay disconnects the commutator 89. and also closes the circuit of relay 96. Relay 96 operating severs wires 280, 281, 282 and 283.

At the fourth rotation of the sending device, a single test impulse is sent over the sleeve side of the trunk to the manual exchange operating relay 81. This relay closes the circuit of the stepping magnet 88, causing the switch X to take one step, thereby disconnecting indicator H, and in its place connecting indicator 1. At the fifth rotation of the sending device, relay 98 operating closes the circuit of the magnet 2285, thereby registering another digit corresponding to the tens numeral of the wanted line. At the sixth rotation, 21 single test impulse operating relay 81 causes the switch X to take another step, disconnecting the indicator 1, and in its place connecting the indicator J. At the seventh rotation of the sending device, relay 98 is operated causing the magnet 286 to register the units numeral of the wanted line.

At the eighth rotation of the sending device, the switch X takes another step, disconnecting the indicator J and in its place connecting the selective ringing device K. At the ninth rotation of the sending device, the magnet 102 operating causes the selective ringing device to step around and connect the proper generator to the ringing relay 95. I

We will assume for illustration that the fourth generator 279 is the one to be selected.

The first step of the device caused by the action of magnet 102 operates cams 100 and 101. The cam 100 in operating, brings the projection 110 into engagement with spring 103, thereby closing contacts 103 and 104, connecting the first generator 276. At the next step, the projection 120 on the earn 101 engages spring 107, thereby connecting springs 106 and 107. however, the spring 103 leaves projection 110 and rests on the surface 112, disengaging spring 103 from contact 104. At the third step the spring 103 enters the detent 111 of the cam 100, thereby closing contacts 103 and 105. At the same instant the spring 107 rests on the surface122, thereby breaking contact with spring 106. At the fourth rotation, the spring 107 enters the detent 121 of the cam 101 and engages contact 108, but at the same time spring 103 rides on the surface of the cam 100 and disengages contact 105. The fourth generator 279 is now connected to the contact of the ringing relay 95. At the first step of the indicators or registers, the lever springs leave the depressions 114, 115, 116, and 117 respectively and ride upon the surface of their respective cams and close the springs associated With wires 280, 281, 282 and 283. The sending device now takes one more step, sending a At the same time,

single test impulse over the sleeve side of the trunk, causing the switch X to take one more step, closing the circuit of the signal lamp 87 by the following path: ground, F, 265, contacts of relay 84, 271, 87, to battery BB. As soon as the shifting switch in Fig- 6 takes this final step, the wiper of the bank P closes the circuit of relay 158 by the following path: battery B, 187, 158 to ground. The operating of this relay connects ground to the magnet 161, and also opens the circuit of relay 157. Under the influence of the magnet 161 the shifting switch starts to rotate and continues to do so until itreaches its normal position. Just before reaching its normal position the wiper of the bank P connects the relay 158 in serieS with release magnet 166, causing the latter to operate and release the switch M. This switch releasing disconnects the operator in the semi-automatic exchange from the primary trunk, (Fig. 2).

The lighting of the lamp 87 at'the manual exchange notifies the operator of a call and she thereupon places the plug PP into the jack corresponding to the number registered on the indicator. In case the jacks 400 at the manual exchange were multipled, the operator would first test the line to find whether it were busy, and if so, would place the plug into the busy-back jack, which would indicate to the calling subscriber that the wanted line was busy. If the wanted line is not busy, the operator places the trunk plug into the jack of the wanted line, thereby placing relays 84 and 401 in series. The operating of relay 401 disconnects the line signal relay and connects the line through to the jack. The operating of the relay 84 connects the commutator 90 to the ringing relay 95 by the following path: ground, 90, contacts of relay 84, 269, contacts of relay 85, 128, to battery BB. Relay 84 also disconnects the lamp 87 and at the same time closes the circuit of the lamp 86 through contacts of relay '83. The operation of 95 at intervals severs the cord circuit and places generator current to the called line, ringing the telephone, which responds to generator 279. The called subscriber removing his receiver during the ringing interval energizes relay 83, thereby disconnecting lamp 86, and energizing relay 85. The energizing of relay 85 disconnects the ringing relay 95, thereby preventing any further action of the same. The calling and called subscribers are now enabled to conv verse. The energizing of relay 83 disconnects relay 96, thereby connecting the interrupter or commutator 89 to magnets 284, 285. 266 and 102. Each of these magnets will continue to vibrate until the lever springs enter the depressions 114, 115, 116 and 117 respectively.

hen the called subscriber hangs up his receiver, the lamp 86 is again lighted and the calling subscriber upon hanging up his receiver releases the automatic switches, at the semi-automatic exchange and operates the lamp S7, notifying the operator that he is through talking. \Vhen the calling subscriber hangs up relay 23 (Fig. 2) falls back and closes the circuit of the release magnet 32 by the following path: battery B, 38, 74, contacts of relay 23, 58, contacts of relay 28, 7 2, 32, 7 5, 41 to ground. The action of this relay releases the primary switch C. Battery is also placed on relay 36 by the fol lowing path: battery B, 38, 7 3, 7 1-, contacts of relay 23, 58, 57, 78, 36 to ground. The action of this relay places ground on wires 7 6, and 77 leading to the manual exchange, simultaneously energizing relays 81 and 98. The joint action of these two relays unlocks relay 82, which upon falling back closes the circuit of the lamps 87 by the following path: ground, 267, contacts of relay 34 271,

S7 to battery BBX The operator upon ge ting the signals, removes the plug PP from the jack, thereby deenergizing relay 84-, which unlocks relay S5 and extinguishes lamps 86, and 87. As soon as the switch 0 restores, opening the springs 38, the two magnets 32 and 35 are placed in series by the following path: battery B, 35,73, 74:, contacts of relay 23, 58, 72, 4-1, 32, 75, all to ground. The action of magnet 35 causes the switch D to restore.

In connection with the apparatus and circuits shown in Fig. 3, it will benoted that I have the various indicators released by the commutator 89, but in practice, it would be preferable to have each indicating magnet provided with its own interrupter or vibrating springs, similar to those of the ordinary vibrating door bell. IVith this latter arrangement, each magnet would control its own circuit and act independently of the others.

Instead of releasing the indicators with interrupted current, I can provide the inclicators with suitable return springs and re lease magnets for restoring purposes. The switch X can also be provided with a re-. lease magnet.

The switch X (Fig. 3) is restored when the called party answers by means of inter rupted current from the commutator 89 directly through the contacts of relay 83. lVire 126, however, instead of leading to a contact in relay 83 can terminate in a contact of relay 96 as do wires 281, 282, 283 and 280.

The particular form of selective ringing device as shown, is simply used for illustration, but forms no part of my invention.

Instead of using the cam arrangement, as shown in the device at K, I can provide a switch similar to X, which will step its wipers around and pick out the generator current in the same manner in which the switch X steps around to pick out the proper indicator. This switch would be restored in the same manner by a bank and wiper corresponding to G. The switch X continues to rotate for restoring purposes until the wiper G comes to rest on an idle contact 600, thereby opening the commutator circuit.

In case the called for party at the manual exchange does not answer, then the calling party upon hanging up releases relay 82, which upon falling back disconnects relay 96 and connects the commutator to the stepping magnets of the indicators and the switch X.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a telephone exchange system, an exchange having a plurality 0tv subscribers lines associated therewith, a second exchange having a plurality of subscribers lines associated therewith, a plurality of digit indicators at such first exchange capable of representing the respective designations of the subscribers lines of said first exchange, setting means for said indicators controlled over an impulse circuit including one conductor of a trunk line connecting such exchanges, and means for shifting said w setting means from one digit indicator to another, controlled over another conductor of such trunk line.

2. In a telephone exchange system, an exchange having a plurality of subscribers lines connected therewith, a second exchange having a plurality of subscribers lines connected therewith, an indicator at the first exchange having a number of digit wheels representing digit numerals, and means for operating said digit Wheels successively from the second exchange, said means including trunks, trunk selector switches, a sending machine, and a keyboard, together with step by step switching apparatus to successively associate the digit wheels with the trunk.

3. In a telephone exchange system, an exchange having a plurality of subscribers lines connected therewith, a second exchange having a plurality of subscribers" lines connected therewith, and a trunk provided with an indicator at the first exchange capable of representing the respective designations of the subscribers lines of said exchange, and means for controlling the indicator, and also provided with means for automatically ringing the indicated subscriber when connection is made with his line.

4c. In a telephone exchange system, an exchange having a plurality of subscribers lines connected therewith, a second exchange having a plurality of subscribers lines connected therewith, a trunk provided with an indicator at the first exchange capable of representing the respective designations of the subscribers lines of said exchange, means for controlling the indicator, and also provided with means for automatically ringing the indicated subscriber when connection is made with his line, selector switches for controlling the connection be tween exchanges over the trunk, and means for automatically disconnecting the ringing means when the called subscriber answers.

5. In a telephone system, the combination of an automatic exchange including a plurality of subscribers lines, automatic switches, a key board associated with said switches for directively controlling the selective action of the same, a manual exchange, an indicator at said manual exchange, adapted to display the numbers of called lines in the manual exchange, a signal associated with said indicator and means for operating said indicator to display the number when the same is set up on the key board of the automatic exchange and means for displaying said signal after the complete number is displayed by said indicator,

6. In a telephone system in combination, an automatic exchange including a plurality of subscribers lines, and automatic switches, together with a key board directly controlling the selective action of the said switches, a manual exchange, trunk lines connecting the manual exchange with the automatic exchange through said automatic switches, said trunk lines terminating at the manual exchange in cord circuits and an indicator at said manual exchange adapted to display the numbers of calling lines, and operable through said automatic switches and said trunk lines from said key board. 7

7. In a telephone system in combination, an automatic exchange including a plurality of subscribers lines and automatic switches, together with akey board for directively controlling the selective action of the switches, another exchange connected with said automatic exchange, an indicator at said other exchange adapted to display the number of called subscribers lines, together with controlling connections from said key board of the automatic exchange to said in dicator, whereby said indicator may be operated to display the number of the wanted line by the setting up of said number upon said key board, means apart from said indicator to indicate the number has been displayed.

8. In a telephone system in combination, an automatic exchange including a plurality of subscribers lines, automatic switches, a key board for directively controlling the selective action of said switches, another exchangehaving a plurality of subscribers lines, trunk lines connecting said other exchange with said automatic exchange through certain of said automatic switches, and an indicator adapted to display the number of called lines located at said other exchange and operable from said key board of the semi-automatic exchange through said automatic switches and comiecting trunks, means for associating said indicator with the called lines, and means exercised said sending device through said automatic;

switches and over said trunk lines, releasing means for said indicator, and means ex ercised over said trunks for controlling said releasing means.

10. In a telephone system in combination, an exchange comprising a plurality of subscribers lines, a plurality of automatic switches, a sending device for directively controlling the selective action of the switches, and an indicator adapted to dis play the number of a called line accessible through said automatic switches and operable t'roni said sending device, together with automatic polystation ringing means similarly accessible and similarly operable.

11. In a telephone exchange system, a plurality of subscribers lines, central station means for interconnecting the same, an indicator at said central station, a sending device adapted to operate said indicatorto display the number of the called line, and means associated with said central station connecting means and operating upon the response of the called subscriber to release said indicator.

12. In a telephone exchange system, a plurality of subscribers lines, central station means for interconnecting'the same, an lndicator at the central station adapted to display the numbers of called'lines, a sending device for operating the said indicator, and a polystation ringing means operated in conjunction with said indicator from said sending device.

13. In a telephone exchange system, a

plurality of subscribers lines, central station means for interconnecting the same, an indicator at the central station adapted to display the number of called lines, a sending device for operating the said indicator, a polystation ringing means operated in conjunction with said indicator device from said sending device, and means associated with said central station connecting means operating when the called subscriber answers to disable said polystation ringing means and release said indicator.

14:. In a telephone exchange system, a plurality of subscribers lines, central station means for interconnecting the same, an indicator associated with said central station means, and comprising digit display devices connected individually with a step by step switch, a sending device adapted to operate said step by step switch and to operate said digit display devices through said step by step switch in succession, together with polystation ringing means also selectively operable through said step by step switch from the sending device.

15. In a telephone exchange system, a plurality of subscribers lines, central station means for interconnecting the same, an indicator adapted to display the numbers of called lines, a sending device, a step by step switch through which said indicator may be actuated from the sending device, said step by step switch having a defined normal position, means operative upon response of 2. called subscriber to release said indicator, and means controlled by the calling subscriber to return said step by step switch to normal.

16. In a telephone exchange system, the combination with an exchange and a plurality of subscribers lines, of an indicator at the exchange adapted to represent the respective designations of the subscribers lines, said indicator having a number of digit wheels and a magnet for each -of said wheels, means for predeterminedly operat ing said magnets in succession to display the designations of the subscribers lines, and means controlled by said magnets for restoring said digit wheels.

17. In a telephone exchange system, a plurality of subscribers lines, a combined indicator and a polystation ringing device, means for operating said indicator to display the numbers of the called lines and for signature l WVitnesses:

ARTHUR L. BRYANT, J. A. WATSON.

Copies of this patent may be obtained for five cents each, by addressing the commissioner of Patents Washington, D. G.

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