Patent GB-200484-A (GB)
Abstract: 200,484. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Nelson, M. L.). July 6, 1922, [Convention date]. Addition to 193,694. Automatic exchange systems; coin-freed systems.-A register-controller of the type which translates the first letters of the name of a wanted exchange into a routing-member is adapted for a system in which the calls to different exchanges contain different numbers of digits. In the example described, calls to an automatic exchange 91 and calls to a non-party manual exchange 93 include only four digits in addition to the exchange designation, while calls to a party-line manual exchange 92 have four digits. It is assumed that both types of manual exchange are equipped with standard 5-digit number indicators, the indicators at the non-party exchange having the fifth-digit lamps omitted but requiring a fifth digit to make them display the called number. It should be understood that the numbers 91, 92, 93 are the numerical equivalents of the first two letters of the exchange-names. The dialling of the first two letters brings the wipers 260 - - 263, Fig. 5, of a Strowger register OR to a corresponding set of terminals, which are jumpered to appropriate terminals at the right-hand side of the translating-frame IDF. If the call is for the automatic exchange 91 the IDF terminals 297, 292, 305, 302 are picked out, of which the first two determine the sending of the routing-member 72, while the terminal 305 determines the skipping of the third routing-digit operations of the sender shown in Figs. 6 and 7. The fourth terminal 302, which is brought into action for a call to any four-digit automatic exchange, determines the energization of a relay 377, Fig. 6, which causes the release of the register-controller and the switching-through of the talking connection as soon as four additional digits have been transmitted under control of the registers DR - - DR<3>, which are set by the number-digits dialled by the calling subscriber. If the call is for the manual party-line exchange 92 the I.D.F. terminals 298, 295, 300, 903 are picked out, of which the first three determine the sending of the routing-number 850, while terminal 303 determines the energization of a relay 378, which enables a fifth number-digit to be sent under control of a register DR<4>, which is set by an extra dialled digit, and since the relay 377 is not energized the release of the register-controller and the switching-through of the call do not take place until this fifth digit has been sent. If the call is for the manual non-party exchange 93 the IDF terminals 298, 295, 299, 306 are picked out, to determine the sending of the routing number 859. Neither of the relays 377, 378 is energized, with the result that after four number-digits have been sent under control of the registers DR - - DR<3> an extra. digit consisting of a single impulse is dispatched, independently of the register DR<4> which has not been moved from normal, and the register-controller is then released and the connection switched through. If the single digit 0 is dialled the register OR rotates automatically to the only set of terminals in its tenth level, and sends the number 46 to route the call to a longdistance operator. The register OR has no terminals in its first level, and, after responding to a single impulse, due for example to an accidental vibration of the calling-subscriber's switch-hook, it automatically restores itself to normal. If the calling subscriber omits to operate his dial the register-controller is released after an interval, or if undue delay occurs between the dialling of two digits a relay 256 is energized and causes the call to be routed to an operator. Prepayment stations, such as that shown in Fig. 1, obtain access to a register-controller through a repeater R, Fig. 2, and hunting switch SS, which differ from the corresponding devices R<1>, SS<1> employed by ordinary subscribers. The pre-payment station must deposit a coin before dialling, to unbalance a differential relay 32, Fig. 2, otherwise the relay 256, Fig. 5, is energized to route the call to an operator, but in the case of longdistance calls (single digit 0) it is unnecessary todeposit a coin. The operations when an ordinary subscriber A', Fig. 3, dials calls to exchanges 91, 92, and 93 will first be described. Call to automatic exchange 91 (routing-number = 72). The non-numerical switches C<1>, SS<1> operate in the usual way. The repeater line relay 125 energizes relay 137, which grounds the holding wire 122 and disconnects it from wire 161. The switching relay 138 grounds the wire 102 to energize relay 204, Fig. 4, grounds wire 104 to energize relay 208, and energizes relay 127 in a circuit 103, 248. Dialling tone is supplied by the transformer TT, Fig. 5, over circuit 249, 101. The dialled digits are repeated by relay 125 over circuit 101, 202, 253 to the vertical and rotary magnets 229, 230 of the exchange register OR and to the magnets 445 &c. of the number registers DR - - DR<3>, Fig. 7, these magnets being brought into circuit in turn by a switch MDC, which is advanced a step at the termination of each digit by its magnet 251, which receives an impulse from the series relay 202 over circuit 2'12, 241, 236, 214. At the termination of the first digit a relay 205 is also energized in this circuit and locks itself. At the termination of the second digit the wiper 254 of the switch MDC connects the grounded wire 104 to a starting circuit 247 to energize relay 375, Fig. 6. A branch of this circuit extends over 354, 351, 264, 263, 283, 297, back contact of relay 467, 367 to relay 380, which energizes relay 379. An interrupter I now intermittingly energizes relay 381 which opens the impulse circuit 248. The first energization of relay 381 is ineffective, since the circuit 248 is also grounded at contact 417 of relay 382, but relay 381 energizes relay 382 sufficiently to attract its sensitive armature 416, and at the next opening of interrupter I relay 382 becomes fully energized through its two windings in series and opens contact 417. The impulses in the circuit 248 affect the relay 127, Fig. 3, which repeats them in the trunk 160, 162 of the selector D, and at the same time relay 381 sends impulses over 413, 415, 369, 477 to operate the counting relays 461 - - 470. These relays are of the type which at first attract only the sensitive middle, armature, and do not become fully energized until the initial energizing circuit is opened to remove a short-circuit from the upper winding. Consequently each impulse in the circuit 369 causes one relay to become locked up over both its windings in series and to prepare a circuit whereby the next impulse energizes the next relay. At the termination of the seventh impulse the relay 467 becomes fully energized and opens the circuit 297, 367 to de-energize relay 380, which disconnects the impulse relay 381 and relay 379 and energizes magnet 350. After an interval the sluggish relay 379 relapses, opens the locking circuit 368 of relay 382 and the counting relays, and de-energizes magnet 350, which moves the switch S to its 2nd position. Ground is now connected over 354, 351, 265, 262, 282, 292, back contact of relay 462, 367 to energize relay 380 again, and the impulse-sending operations are repeated, two impulses being now sent. The energization of the counting relay 462 de-energizes relay 380 as before, and after an interval relay 379 relapses and moves the switch S to its 3rd position. Ground is now connected over 354, 351, 266, 261, 381, 305, 352, 349, 350 to move the switch S to its 4th position, in which ground is connected over 354, 351, 267, 260. 280, 302 to energize relay 377, which locks itself and closes a circuit 391, 352, 349, 350 to move the switch S to its 5th position. In the 5th, 6th, 7th, and 8th positions the four number-digits are sent under control of the registers DR - - DR", the relays 379, 380, 381, 382 operating as before described, and the switch S then moves to its 9th position and closes circuit 393, 353, 243 to energize relay 376. This relay locks itself to the wire 102 and grounds the wire 101 to energize relay 126, which locks itself and switches the connection through the repeater R<1>, also connecting the wire 122 to 161. Relays 125, 137, 138 relapse and the switch SS<1> releases the registercontroller. The removal of ground from circuit 104, 247 de-energizes relay 375, which drives the switch S to normal, and the removal of ground from circuit 102 de-energizes relay 204, which grounds the circuit 242 to release the switches MDC, OR and DR - - DR<4>. Call to manual party-line exchange 92 (routing- number = 850). The operations differ only in the following respects. The third wiper 261 of the register OR is connected over 277 to the wire 300 instead of to the skip wire 305, so that a third routing-digit 0 is transmitted in the 3rd position of switch S, and the fourth wiper 260 is connected over 276, 303 so that in the 4th position of switch S relay 378 is energized instead of 377. Consequently, since contact 393 is not closed the register controller is not released in the 9th position of switch S, but a fifth numberdigit is send under control of the register DR<4>, which was set by an extra dialled digit signifying the position of the wanted subscriber on his partyline. The switch S then moves to its 10th position and grounds the release circuit 243. Call to manual non-party exchange 93 (routing- number = 859). The operations differ only as follows. The fourth wiper 260 of the register OR is connected over 272 to the skip wire 306, so that neither of the relays 377, 378 is energized, but the switch S is driven at once from its 4th to its 5th position over circuit 354, 351, 267, 260, 272, 306, 352. Since relay 378 is not energized, relay 380 is energized in the 9th position over circuit 354, 351, 364, 396, 291, 475, 367 an