Patent GB-209040-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1923-10-29
Abstract: 209,040. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Gardner, J. E.). Dec. 23, 1922, [Convention date]. Automatic exchange systems.-Relates to systems in which the wanted exchange is selected by dialling the first three letters in its name, as described in Specifications 193,694, 194,427, 194,580 and 211,189. According to the present invention, one or more digits directly control a numerical selector, subsequent digits controlling a register translating device by which the call may be routed. The number of alternative routes available after the first digit is thus reduced, and special register translators are devised for dealing with the particular cases which arise on each route, some connections being possible without the aid of any register. The registers may suppress or add digits as required or may translate the designation number into a routing number. A trunk may terminate in two non-numerical switches having access to different exchanges, one or other switch operating according to the setting of the registers. In tandem trunking in which calls are routed through two or more exchanges in series, each incoming trunk may terminate in a " traffic separator " which responds to distinctive currents (such as positive or negative current over one or other line, or currents over the loop circuit or one lead with earth return) and extends the call to the desired exchange. After the exchange digits have been registered, the registers may be released for common use as soon as the controlling operations catch up the dialling operations of the subscriber, the selection of the exchange being controlled by the registers only and the selection of the line in that exchange by the registers or by the subscriber. The individual registers may be used more than once in registering a given number; thus four registers may register a seven-digit number, each register being released as soon as its controlling action is finished so that it may be set by a subsequent digit. Three arrangements are described. First system, Figs. 5, 6, 7, 8, in which the register introduces an extra digit in the called number but without translation, the second digit operating the trunking selector K<3>, Fig. 5, and also a second selector at the distant exchange. A calling subscriber is connected by his line switch to an idle first selector, which is operated in the usual manner by the first set of impulses to select an idle trunking-selector K<3>. The line relay 101 energizes relay 102 which is made normally slow to release owing to its upper winding being short-circuited by the switching relay 100. Relay 102 causes switch SS to connect up an idle register set comprising four registers M<2> - - M<5>, controlling sequence switches Z, Z<1>, and an impulse sender S. The second set of impulses is repeated by the relay 101 to the vertical magnet 108 of the selector K<3> which selects an idle trunk on the desired level. Setting of registers. The second set of impulses is also repeated over circuit 118, 120, 140, 200, 270, 400, 402, 350 to magnet 305 of register ill2. At the end of each set of impulses, relays 400, 401, Fig. 8, cause magnet 403 to move switch Z<1> to its next position, so that successive sets of impulses pass to the registers M<3>, M<4>, M<5>, M<2>, M<3>, M<4> respectively. Relays 300 - - 303, energized in the off-normal positions of the registers, prepare circuits for the release magnets 304, 306, 308, 311 and also ground wire 264 to energize relays 220, 219, Fig. 6. Controlling operations of registers. When register M<2> has been set, relays 400, 401 energize relay 218, Fig. 6, which locks up and closes a circuit through an interrupter I for relay 415, Fig. 8, which causes magnet 426 to step round the sender S until its arm 410 engages a contact grounded by register M<2>, whereupon relay 417 opens the circuit of relay 415 and returns the sender to normal. The relay 415 also sends impulses over circuit 421, 419, 273, 199 to relay 103, Fig. 5, which repeats them over the selected trunk to a second selector at the next exchange. When the impulses cease, a relay 217, Fig. 6, energized in parallel with relay 103, causes magnet 210 to move switch Z to release the register M<2> and earth the wiper of register M<3>. Successive sets of impulses are repeated in a similar manner. A.fter the last set of impulses, or if the controlling operations catch up the dialling operations, all the relays 300 - - 303 are de-energized and ground removed from wire 264, so that relay 220 closes a circuit over wire 197 for the switching relay 100, which locks up, extends the calling line to the selected repeater, and disconnects relays 101, 102 which restore the switch SS and the registers to normal condition. Operation if all trunks are busy. If all trunks in the selected level are busy, the selector K<3> rotates an additional step, a cam controlling con. tacts 134, 135 to restore the registers and connect a busy tone to the calling line. Second system, Figs. 9 - - 13, in which the register translates the exchange designation, adding or suppressing sets of impulses as required according to the routing of the wanted exchange. Assuming that the call has been extended over a particular level of the first selector, determined by the first letter of the wanted exchange, to the trunking-selector K<1>, Fig. 9, the line relay 501 energizes the slow-release relay 502, which causes switch SS<1> to connect up an idle register set comprising four registers M<5> - - M<9>, Fig. 11, sequence switch Z<2>, Fig. 12, impulse-sender S<1>, a relay group G<3>, Fig. 10, which controls successive controlling operations of the registers, and a set, of relays G<5>, Fig. 11, which effect the necessary translation between the sets of impulses representing the second and third letters of the wanted exchange and the sets of impulses which select, it. Setting of registers. The second set of impulses is repeated bv line relay 501 over a circuit 512, 515, 618, 694, 850, 878, 804 to magnet 764 of the register M<5>. Successive sets of impulses are repeated over wiper 878 in its several positions to the registers M<6>, M<7>, M<8>, M<5>, M<6>, M<7> respec. tivelv. Relays 730, 701, 787, 797, energized in the off-normal positions of the registers, prepare circuits for the release magnets 763, 702. 794, 796 and earth the wire 686 to energize relay 663, 662, Fig. 10. Arrangement of translating relays G<5>, Fig. 11. The relays 725 - - 729, which are only energized when both their windings receive current, are connected to contacts engaged by wipers 765, 767 of registers M<5>, M<6>. These relays selectively earth contacts in the path of the sender S<1> and determine the number of sets of impulses transmitted by controlling the relays 625 - - 628, Fig. 10, which determine the successive controlling operations of the sender. Normal controlling operation of registers. After the registers M<5>, M<6> have both been set, relays 850, 851 earth the wipers 765, 767 over a circuit 685, 648. 697, 856, 858, thereby energizing that one of the relays 725 - - 729 having both its windings connected to contacts engaged by wipers 765, 767. The particular relay locks up and earths the wire 675, thus energizing relay 661, Fig. 10, which starts the sender S<1> by closing circuit I<1>, 865, 698, 671, 673. The relay 865 causes magnet 861 to step round the sender S' until its wiper 859 engages a contact connected by one of the relavs 725 - - 725 to the lead 677 grounded at the back contact of relay 629, Fig. 10, whereupon relay 867 disconnects relay 865 and returns the sender to normal. The relay 865 also sends impulses over circuit 869, 699, 617, to relay 503, Fig. 9, which repeats them to relay 504, and the vertical magnet 531 of selector K<1>. The selector K<1> rotates to find an idle trunk in the selected level, the subsequent operation depending on the level selected and the setting of the registers. During the impulse transmission, a relay 660, Fig. 10, energized in parallel with relay 503, causes relay 629 to attract its armature 651 only, the relay being fully energized over 651, 657 when the relay 660 de-energizes. Relay 629 removes ground from the wipers 765, 767 and from the lead 677 by which one of the relays 725 - - 729 controlled the first emission of impulses. and earths the wiper 766 of register M<5> over 681, 631, 652, 657. The sender S' operates as before until its wiper 859 reaches the contact grounded by wipar 756, impulses being sent over lead 699 to relays 501, Fig. 9, and 660, Fig. 10 in parallel. Relay 660 controls relay 625 in the same way as it did relay 629, and at the end of the impulses relay 625 energizes and (1) locks up, (2) connects ground to wiper 768 of register M<6> instead of wiper 766, and (3) releases register M<5> by energizing its release magnet 763. Successive sets of impulses are sent out under control of wipers 768, 770, and 772 of registers M<6>, M<7>, M<8>. relays 626, 627, 628, Fig. 10, energizing in succession to release the used register and ground the wiper of the next. The relay 628 opens the locking circuit of the relays 625, 626, 627 so that these again control the registers M<5>, M<6>, M<7> but as the relay 629 remains energized the translating relays play no part in the second cycle of operations, which otherwise proceeds as before. After the last set of impulses, or if the controlling operations catch up the dialling operations, all the relays 730, 701, 787, 797 are deenergized and the removal of ground from lead 686 de-energizes relay 663 which closes over lead' 616 a circuit for the switching relay 500, Fig. 9. This relay locks up, extends the calling line to theselected repeater, and disconnects relays 501, 502, which restore the switch SS<1> and registers to normal condition. Discriminating operations of registers. In the normal operation as just described, the registers send out one more set of impulses than they rece