Patent GB-191210444-A (GB)
Title: Improvements in Impulse Transmitters for Semi-automatic Telephone Systems.
IPC: H04M1/272
Filed: 1911-05-02
Granted: 1912-11-07
Abstract: 10,444. Siemens & Halske Akt.-Ges. May 2, 1911, [Convention date]. Semi-automatic exchange systems.-In an operator's keyboard impulse-sending set, in which impulses corresponding to the digits of the wanted subscriber are sent by means of a feeling-device, such as a relay set or rotary step-by-step switch, a single feeling-device is used for all the digit places and is restored to its normal position as soon as it has reached the depressed key on the row which is being tested at that time, and repeats the process for each succeeding digit. Two arrangements of the impulse transmitter are described, in one of which the feeling-device, and also the means for associating it with the different digit keys, consists of a relay set, and the other in which both these devices consist of rotary stepby-step switches. The first arrangement is shown in Fig. 2, the four rows of ten digit keys T, H, Z, E being associated with four digit relays I<1>, II<1>, III<1>, IV<1>, which control the transmission of the impulses for their respective digits. The keys are also connected with the contacts of ten cipher relays I, II .. X, which are energized in sequence by impulses from the commutator sections U<2>, U<3>, until the relay corresponding to the depressed key is reached, when the impulses sent by the commutator U<1> to the selectors are cut off by the excitation of the relay J. The process is then repeated for each of the digits. General operation of the system. A calling subscriber is shown as connected by a preliminary selector VW, Fig. 1, to a selector trunk a, b, which in turn is connected in known manner by a finder-switch DW, Fig. 2, to the operator's apparatus. The calling-lamp L is thus energized by current passing through the relay P, and contacts 12, 11 of the first selector. The relay P connects the operator's talking set h. m to the calling line until after the first movement of the selector. Assuming that connexion with subscriber No. 2345 is required, the operator depresses the respective keys as shown in Fig. 2, the depression of the units key momentarily closing a contact s<1> so as to energize the relay S in series with a relay T which disconnects the calling line during the impulse-transmission. The relay S locks up over its contact 15, disconnects at 16. 17 the operator's talking set, and connects the trunk a, b to the impulse-sender at 18. 19. The trunk n being thus earthed over contacts 42, 18, 20, the relay A energizes in series with the differential relay XO, which closes a hold-on circuit for the relay B, and also connects the battery over contact 31, winding 30, and contacts 28, 19, 27 to winding 26 of a relay E, which is energized over contacts 25, 24 as soon as the brush 22 is earthed bv the commutator U<2>. The relay E closes a circuit through its holding-winding 33 and a relay G, which by closing a contact 36 connects a resistance 37 in parallel with the winding 33 of -the relay E so that the relay G remains energized when the latter de-energizes. The relay G also opens at 27 the circuit of the winding 26, but maintains that of the relay XO by earthing contact 35. The thousands digit relay I' is then energized over contacts 38, 39, 40 and the dotted lead to the earthed contact 15. The excitation of the relays E, G, I<1> takes place while the brush 22 is earthed by the hatched portion of the commutator. During this time the relay A is energized over the contacts 42, 18, and the brush 21. First selector. As the commutator U<1> rotates, the relay A is intermittently de-energized, and repeats the impulses to the vertical magnet H, the relay XO keeping the side-switch magnet 57 energized. After the first interruption of the current in the relay A, the commutator U<3> energizes the cipher relay I, which closes a holding-on circuit over contacts 44, 45, opens at 46 the holding-circuit of the relay E, and prepares a circuit at 48 for the relay II, which is energized when the spring 22 is earthed. The relays III, IV .... X are thus alternately energized by impulses received from the springs 23, 22 until the relay corresponding to the depressed thousands key, in this case the second, is reached, when a circuit is closed for the relay J over the contact 52, depressed key, contact 51, to earth at 15. The relay J cuts off the impulse-transmitter at 42, 28, bridges the trunk a, b, and short-circuits at 79 the relay G, which after a moment disconnects the relav II and consequently the relay J. The relay G may be sufficiently sluggish to allow a constant time for the hunting movement of the selector to take place before the relay J is de-energized, but preferably the arrangement shown in the drawings is adopted, in order that the next set of impulses may be sent out immediately the rotary movement of the selector is arrested. The relay XO is de-energized when the bridging contact is closed, and the magnet 57 moves the side-switch into its second position in which the rotary magnet D is energized, the magnet 57 being again energized over a contact 58. When an idle trunk is found, the test-relay C disconnects the magnet 57 and the side-switch moves into its third position. Second selector. The relays A, XO of the second selector are now energized over the trunk a as before, and the relay XO closes a circuit through its other winding, the trunk b, contact 27, relay F, contact 24 (relay I<1> being now energized) as soon as the brush 22 is earthed. The operation then proceeds as before except that the relay F replaces the relay E, the simultaneous excitation of the relays F, G energizing the hundreds digit relay II<1>. Connector. When an idle connector is found, its relays A, XO are energized over the trunk a as before, and, when the spring 22 is next earthed, the relay XO closes a circuit which now includes the relay E and contact 24, the relay I<1> having now de-energized. The relays E, G energize the tens digit relay III<1>, and the trunk a is intermittently earthed by the spring 21 until the relay IV corresponding to the depressed tens key is reached, when the relay J is energized as before. The closure of the bridging-contact causes the side-switch of the connector to move into its second position, but in this case there is no interruption of the current in the trunks a, b since the relays A, B are permanently connected to these trunks. When the relay J de-energizes, the impulse transmission is immediately continued, the relays F, G, IV<1> being energized as before. When the relay J is again energized, it releases the relays F, G, IV<1>, causes the movement of the connector side-switch into its third position, and also opens at 14 the holding-circuit of the relays S, T, this circuit having previously been maintained over a shunt contact 78 on the relay IV<1>. The impulse-sender is thus returned to its normal position. The test of the called line and the release of the connexion are effected in known manner.