Patent GB-146517-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1920-07-05
Abstract: 146,517. Western Electric Co., Ltd., (Assignees of Polinkowsky, L., and Matthies, W. H.). June 14, 1919, [Convention date]. Telephone systems; automatic exchange systems; metering systems.-In a system comprising satellite offices, number registers at a satellite can, according to the number to which they are set, either control local selectors to set up a connexion not involving main exchange trunks, or can repeat their record to registers at the main exchange. The invention is described as applied to a system of 20,000 lines, numbered 10,000, to 29,999, of which 400 lines, numbered 22,500 to 22,899, are allotted to the satellite under consideration. To establish a local connexion, the calling line 240, Fig. 1, is connected by first and second line-finders to a group-selector, Fig. 2, which is associated by a switch 280 with an idle register set, Figs. 3 and 4, of which the last three registers 120, 130, 140 control the group-selector and a local final selector, Fig. 5. On the other hand, in making a main-exchange call, the satellite registers cause the tripping of the first set of brushes of the group-selector, which hunts in its first level for an idle main exchange trunk. All the exchange trunks are wired to this level, so that in the case of main exchange calls, the satellite group-selector exercises no numerical function. The satellite registers then transfer their records over the selected trunk to corresponding main exchange registers 700-740, Fig. 8, (associated with the trunk by a switch 580, Fig. 6) which control group and final selectors, Fig. 6, at the main exchange to complete the connexion. The transfer of the register records is effected by means of a transfer switch 150 shown at the right of Fig. 4, which moves through a cycle at each transfer operation, restoring a satellite register to zero in the first part of its movement and positioning the corresponding main-exchange register during the second or complementary part of its movement. The system is of the type in which the registers, both satellite and main-exchange, are set to the complements of the digits of the wanted number. The selectors are 200 point switches, the registers being arranged to effect the necessary translating operations, as fully described in Specification 141,081. Local connexion; selection of idle-group-selector, Fig. 2, and idle register-set, Figs. 3 and 4. The first and second line-finders operate in known manner. To reduce the number of second finders hunting simultaneously, these finders are related in pairs in such a way that if both finders of a pair are idle, the controlling sequence switch 220 of only one of them is in its 1st position, the switch 220 of the other finder being detained in its 18th or subnormal position from which it is advanced to normal after the first finder has made a connexion. When a second finder engages calling terminals, test relay 232 becomes energized, and in conjunction with starting-relay 222 closes a circuit to move switch 220 to its 4th position, energizing relay 235, de-energizing-relays 222, 232, and closing a circuit 225, 245, 281 for the hunting switch 280. When this switch reaches a position belonging to an idle register set (for example the 1st or 7th positions, to both of which the register set shown in Figs. 3 and 4 is connected), relay 234 becomes energized in series with relay 323, Fig. 3, (in a circuit 322, 293, 282, 219, 281) and energizes relay 232 which opencircuits switch 280 and drives switch 220 to its 5th position, connecting the calling line over contacts 236, 239 to the stepping relay 325, Fig. 3. The appropriated register set is rendered non- selectable by the connexion to its test circuit of a low-resistance circuit through the left-hand winding of relay 234 and relay 232. Setting of registers. Relay 323 closes a circuit over its right-hand winding to move the sequence switch 320 into its 3rd position in which relay 326 is energized and completes the circuit of the ten thousands register 100, Fig. 4, over the contact 328 top, right-hand winding of differential relay 329, contact 330 top, and the armatures of relays 326, 325. Relay 337 is energized in a branch of the same circuit. The register 100 moves from position 0 to 1 under control of its local contact 101, the closure of the latter shortcircuiting the right-hand winding of the relay 329, which is thus unbalanced and attracts its armature, opening the circuit of the register 100, so that this comes to rest in position 1. The subscriber hearing the dialling tone, transmitted by the interrupter 333 over the transformer 324, then transmits the selecting impulses in the usual manner. At the first interruption of the line circuit, relay 325 opens the circuit of the left-hand winding of the relay 329, which releases its armature to prepare again the circuit of the register 100. On the line circuit being again closed, the register moves into its next position causing the energization of relay 329 as before. This process is repeated for each impulse transmitted, at each closure of the line circuit the relay 337 energizing to maintain the register 100 and the relay 329 energized until the register 100 has advanced a full position. As a local call is being made, the first digit is 2 and the register 100 is advanced to its 8th position. The last line interruption being of relatively longer duration, relay 325 is de-energized for a time sufficient to energize relay 334, which causes relay 323 to complete the circuit of switch 320 which moves into its 5th position. As the switch moves through its 4th position, the register 100 is advanced an additional step to its 9th position by the momentary closure of the contact 330 bottom. In the 5th position of the switch 320, the thousands register 110 is energized over the contact 328 bottom, and is set in the same way as register 100 to its 8th position, after which the switch 320 advances to its 8th position wherein the hundreds register 120 is set, and then to its 10th and 12th positions wherein the tens and unit registers 130 and 140 are set. Group-selector, Fig. 2. As soon as the setting of the hundreds register has been completed, switch 320, moving out of its 8th position closes a circuit 338, 103, 352 to drive switch 350 to its 2nd position. Since the wanted number belongs to the calling satellite office, register contacts 106, 116, 127 are closed in a series circuit through relays 383, 382 and these relays are now energized by the transitory closure of contact 372, and lock themselves through contact 369. Relay 382 drives switch 350 into its 5th position, so that the selecting operations which normally take place under the control of registers 100, 110 in its 3rd and 4th positions are omitted, and the groupselector, Fig. 2, is controlled by the hundreds register 120 to select a local final selector, Fig. 5. As switch 350 runs through its 4th position, a circuit (122, 375, 126, front contact of relay 383, 369) is closed for driving the hundreds register 120 from any odd position to the next even position. These two operations are for purposes of translation. Whilst the switch 350 is passing to its 5th position the relay 357 is energized to maintain the fundamental circuit open. In position 5 of the switch 350 the relay 357 is de-energized and relays 222, Fig. 2, and 355, Fig. 4, are energized in series in a fundamental circuit 247, 283, 296, 380. Stepping-relay 355 opens the circuit of relay 359 which was energized in position 2 ofthe switch 350, whilst relay 222 moves switch 220 to its 6th position in which the trip spindle power magnet 248 is energized. The trip spindle rotates, intermittingly grounding the fundamental circuit to de-energize the stepping-relay 355, which controls relays 359, 362 in the same way that relay 325 previously controlled relays 329, 337, to advance the register 120. When the register reaches normal, the switch 350 is moved into position 6 by contact 124, and relay 357, energized in a branch of the same circuit, opens the fundamental circuit so as to de-energize relay 222, which causes the switch 220 to be advanced to its 7th position, wherein relay 222 is re-energized in a circuit 219, 282, 293, 340, and the power magnet 241 is energized to rotate the brush carriage to trip the selected brushes and to find an idle trunk. On reaching the test terminal of an idle trunk, the test relays 234, 232 are energized to arrest the rotation and render the selected trunk busy to other groupselectors. The switch 220 is then moved to its 9th position, and if the units digit has been registered and the switch 320 has reached position 14, a circuit is completed for the switch 350 over the contacts 352, 341. The swith 350 moves to position 7 in which the fundamental circuit is extended over both speaking wires to the final selector, Fig. 5, over relay 452, brush 267, contact 247 top, conductor 296, stepping-relay 355, contact 356 bottom, conductor 297, brush 268, and contact 458. Final selector, Fig. 5. Relay 452 causes the switch 450 to be driven into its 2nd position in which the power magnet 448 is energized. As the tripping spindle rotates, the fundamental circuit is intermittingly grounded in the usual way, and the stepping relay 355 repeatedly. closes the circuit of the tens register 130. When the register reaches normal, switch 350 and relay 357 are energized in parallel over contact 134. The switch 350 moves to its 9th position, whilst relay 357 opens the fundamental circuit, thereby deenergizing relay 452, which causes switch 450 to be driven to its 5th position, wherein the brush carriage power magnet 461 is energized. The fundamental circuit is re-established and as the brushes rotate, the stepping-relay 355 repeatedly closes the circuit of register 140. If the hundreds digit of the wanted number is even, the relays 373, 374 are not energized, and when the regi