Patent GB-230006-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/42
Filed: 1924-09-15
Abstract: 230,006. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Richardson, R. G., and Bellamy, J. I.). Feb. 25, 1924, [Convention date]. Automatic exchange systems; selectors.-In a system employing register-controllers of the codetranslating type in which the value of the translated digits is determined by arbitrary crosswirings at a distributing frame, a single distributing frame is used in common for a number of register-controllers and the code-register switches of the various register-controllers are mounted side bv side in association with terminal banks multipled to one side of the common frame. The selection of the terminal in the bank of the sending switch which will determine the value of any particular translated digit is controlled by a set of relays connected to the multipled side of the distributing frame over wipers of the code-register switch, the said switch being automatically moved on through a short step at the end of each digit so that the same set of relays may operate again to control the transmission of the next translated digit. The release of the register-controller is controlled externally from switches in the talking connection so that release will always take place automatically as soon as the connection has been completed in spite of the fact that subscribers' numbers even in the same exchange may contain different numbers of numerical digits. In the system shown, a calling subscriber A, Fig. 1, is extended over a line switch C to a first selector D and over a further line switch SS to a registercontroller, Figs. 3-6, the call being completed in the case of a called subscriber A<1>. Fig. 2, over exchange selectors D, E, G, repeaters F, F<1>, local selectors I, J, and a connector K. The code-register switch OR, Fig. 5, is of Strowger type having a long-step rotary magnet 441 operated by the second code digit and a short-step magnet 440. Corresponding to each long step there are three positions of the wipers 451 - - 454 to which they are automatically moved under control of the short-step magnet 440, each position corresponding to a particular translated routing digit, the value of which is determined by relays a - - d which are operated over wipers 451 - - 454, the associated bank contacts, the leads 461 - - 484 and the common distributing frame IDF. After the transmission of three routing digits, the switch OR is disconnected and the switch S<1> which controls the re-transmission of the numerical digits recorded on the register DR1 - - DR4 is brought into operation. The means for controlling the release of the register-controller comprises a polarized relay 304, Fig. 4, which is operated owing to a reversal of current when a connector is seized, and by means of two two-step relays 303, 302, causes the register-controller to be released after the transmission of two more digits. The system provides for calls to a complaint or information operator, to a toll-recording operator in which case release of the register-controller takes place under internal control, and to the fire department in which case two extra digits are inserted and are subsequently absorbed, the digitabsorbing apparatus thus taking the place of a connector in controlling the release of the register-controller. Means are provided, in case a calling party omits to dial, for releasing the registercontroller after a timed interval and for preventing the subscriber from subsequently controlling the selector D directly. In a modification, Figs. 8 and 9, the release of the register-controller when the maximum number of numerical digits is employed is controlled in the usual way by the movement of the control switch S<1> after the last digit has been transmitted, but in the case of a call involving less than the maximum number, the release is immediately effected by a momentary current reversal sent back from a connector K<1> or from an operator's circuit HC, Fig. 9. In the following detailed description, it will be assumed that the subscriber A in calling subscriber A<1> dials a code the numerical equivalent of which is 33, followed by numerical digits 1234. Setting of register-controller. The calling subscriber A is connected in known manner over his line switch C to a relay group TC at which relays 25, 26 operate, and thence over a similar switch SS to an idle register-controller, Figs. 3-6. A polarized relay 28 having its left hand winding energized in parallel with a resistance 29 and its right-hand winding over resistance 42 and the grounded lead 22 is unable to operate, the two windings being in opposition. Switching relay 46 of the switch SS grounds wiper 54 to mark the register-controller busy, and this ground is extended over conductor 58 to operate relay 321 and the upper winding of polarized relay 304. Relay 46 also connects up the windings of the line relay 63 of selector D over conductors 56, 57, contacts 329, 331 and the lower winding of polarized relay 304 in parallel with resistance 306, the direction of currents through the windings of relay 304 being such that it operates. The three impulses of the first exchange digit are repeated over conductor 59 and wiper 207 to the vertical magnet 438 of the register OR, switch S advancing its wipers one step at the end of the digit so that the three impulses of the second exchange digit are repeated to the long-step rotary magnet 441 and advance the wipers 451 - - 454 into engagement with the 7th set of terminals in the third level. The four numerical digits are then repeated in similar manner to the digit registers DR1 - - DR4. Transmission of translated digits. When switch S moves into its third position after the last exchange digit has been recorded, wiper 206 completes an interrupter circuit 325, 236, 235, 305, for relay 322 which in turn energizes magnet 338 of the sending switch S<2>. At the succeeding deenergization of magnet 338, wiper 340 completes a circuit for relay 323 which removes a shortcircuit 331 from the impulse contacts 329, so that at each succeeding operation of relay 322 an'impulse is sent out to the selector D. Wiper 206 of switch S in its third position also completes a circuit over contact 308 for relay 455 which connects up the wipers of the register OR and causes the operation of relays a, c over multiple leads 461, 463 and the common frame IDF. Relays a, c cause the grounding of the second counting conductor 492 so that, after two impulses have been sent out, relay 324 energizes over this conductor, opens the circuit of sending relay 322 and completes a restoring circuit for switch S<2>. Shortly after a wiper 340 reaches normal, relay 323 relapses and completes a circuit 310, 337, 333, 224 for short-step magnet 440 which advances wipers 451 - - 454 one short step on to their 8th terminals, relay 455 being meanwhile short-circuited to release relays a, c. The selector D is operated in the usual manner to extend the connection to a selector E at which the battery and ground connections are reversed so that relay 304 de-energizes and releases relav 303 which was operated, at first partially by the operation of relay 323 and then wholly by the operation of relay 324. When relay 455 again energizes, relay a energizes over lead 471 to ground the fourth counting conductor 494 so that a second digit of four impulses is transmitted to operate selector E, after which the register DR moves to its 9th position. Selector E extends the connection to a repeater F at which relays 102, 103 energize, the latter closing the circuit of the lower winding of polarized relay 101 the upper winding of which is in series with the reversed battery and ground at the selector G so that relay 101 operates, reverses the connections of relay 102 and causes relay 304 to operate again. When relay 455 operates after wipers 451 - - 454 have moved to their 9th position, relays a, d, energize over leads 481, 484 to ground the counting conductor 493, so that three impulses are sent to operate selector G to extend the connection over a repeater F'' to an incoming selector I. When selector G has fully operated and its reversed line relay has been disconnected, relays 101, 304 de-energize. Relay c is at this time connected over lead 483 to a reversed battery of half the main voltage so that relay c operates only partially to close its contacts 1 without operating contacts 2, thereby completing a circuit 310, 337, 333, 226, 230, for relay 301 which locks up, connects up the magnet 208 of the numerical-digit controlling switch S', and disconnects the register OR. Re-transmission of numerical digits; release of register-controller. The re-transmission of the numerical digits in accordance with the setting of the registers DR1 - - DR4 now takes place in a similar manner, wipers 210, 211 of switch S' being advanced one step at the end of each digit. The first two numerical digits cause the operation of switches I, J to extend the connection to a connector K at which the reversal of the connections causes the response of relays 101, 304. The response of relay 323 at the beginning of the tens digit causes the partial operation of relay 303 which at the end of the digit operates completely, so that at the beginning of the units digit relay 302 partially operates and at the end thereof operates completely and grounds conductor 59. This ground connection causes the response of switching relay 27, Fig. 1, which disconnects relay 25 so that the succeeding relapse of relay 26 de-energizes relay 46 and the removal of ground from wiper 54 makes the register-controller again available, the release of relay 321 closing restoring circuits for switches OR, DR1 - - DR4, S, S<1>, S<2>. Completion of connection; metering. The operation of the connector K to select, test and ring the wanted line takes place in known manner. When the called subscriber replies, back bridge relay 124 reverses