Patent GB-198401-A (GB)
Title: Improvements relating to impulse senders for automatic telephone systems
IPC: H04M1/272
Filed: 1922-02-02
Abstract: 198,401. Siemens Bros. & Co., Ltd., Christian, D. A., and Berry, J. Feb. 2, 1922. Semi-automatic exchange systems.-In a keyboard impulse-transmitter of the type in which the keys are multipled to the cipher switches of several impulse senders, each switch of an assigned sender being first moved to mark a depressed key and then to normal position during the transmission of impulses, a condenser in parallel with each marking circuit is charged upon momentary depression of the corresponding key and acts upon the test relay which stops the first movement. The apparatus described is for use at a position with 30 cord circuits, a calling kev CK being provided for each set of 10, a. single keyboard KB and several sending sets SP. An assignor AS acts to couple up an idle sender SP, Fig. 3, and associated junction seeker JS, Fig. 1. Connection to idle sender SP. Upon plugging into the jack 31 of a junction to the automatic switches and depressing the proper key CK, one of the relays such as Q<1> is energized, connecting up the rotary magnet DM' associated with the relay Q<1> in the junction seeker JS then engaged by the assignor AS. The corresponding switch A' - - D<1> is rotated until the C<1> wiper reaches the contact earthed by the calling key CK, whereupon relays C, DF are energized in series. The relay DF releases the relay Q<1> and connects the impulse circuit to the junction, while the relay C opens the driving circuit, earths the test wire 35 by short-circuiting its high resistance winding, and energizes a relay E in the sender controller SC, Fig. 2, lighting a coupling lamp'36 to indicate that the calling key mav be released and the number set up on the keyboard KB, Fig. 3. Control of cipher switches by the keyboard. The condensers K are discharged bv the energization in parallel of relays Z upon operation of the relay Q<1>. Upon depression of a key in each bank, the associated condensers are charged by battery on the common wire 22, and each is connected to the common wires 20, 23, 24, 25, connecting up the rotary magnets DMM, DMH, DMT, DMU, and driving the cipher switches until the marked contacts are reached, whereupon the test relays M, H, T, U are operated by the discharge of the condensers K, opening the driving circuits. Transmission of impulses. A relay S, Fig. 2, now becomes energized over the contacts m<4>, h<4>, t<4>, u<4>, and operates the rotary magnet DMP of the sender controller SC. When the fourth position is reached. a relay P energizes over the wiper CC and contact m<3>, opening the driving circuit and connecting up the impulse relay A, which sends impulses over the junction and also to the magnet DMM of the thousands switch. When the latter reaches normal position, the circuit of the relay M is broken, releasing the relay P, which open-circuits the impulse relay A and again connects up the rotary magnet DMP. When the switch SC reaches the third position after making a complete revolution, the relay P becomes energized over contacts h<3>, m<3> with similar results, the relay H being released, and the remaining impulses are sent in a similar manner. The coupling lamp 36 is caused to flicker by the interaction of the relays A. E to bring a resistance into the circuit at. each impulse. Release. The controller SC then moves until, in the tenth position, a release relay FR is energized over the contacts h<3>, m<3>, t<3>, u<3>, releasing the relay S which pulls up the controller in normal position, and breaking the circuit of the relays C, DF which restore the junction seeker JS and cord circuit to normal. Assignor AS. Upon energization of the relay S, the assignor relay AP, Fig. 1, is released, connecting up the rotary magnet DMA, causing the assignor to move round until the relay AP is again connected to battery at an idle sender controller. If all the junction seekers are busy, a relay AQ relapses and the relay AP energizes on the first contact being reached. Transmission of one or two digits only. For the sending of a single digit, a particular thousands key is assigned, and a relay MD, Fig. 3, is provided which becomes energized over the C wiper upon operation of the test relay M, and connects up the relay S. After the sending of impulses, the relay M de-energizes and release occurs as before. To send two digits, a relay HD connects up the relay S after setting of a particular thousands key and any hundreds key. Correction of wrongly set up numbers. Depression of a wipe out key WOK, Fig. 3, operates a relav WO which releases the test relays M, H, T, U, so that the cipher switches return to normal, and discharges the condensers K by the energization of the relays Z. But this relay has no effect if the relay S has already operated.