Patent GB-191119185-A (GB)
Title: Improved Circuit Arrangements for Automatic Telephone Exchanges.
Filed: 1911-08-26
Granted: 1911-12-14
Abstract: 19,185. Siemens & Halske Akt.-Ges. Aug. 27, 1910, [Convention date]. Automatic exchange systems; metering systems.-In systems in which a relay repeater is arranged between the preliminary selector or call-finder and the group selector, the nearer and further parts of the speaking leads are connected together, when all the selecting and controlling impulses have been transmitted, by means of relays at the repeater which are energized from the connector when the latter has been set upon the called subscriber's line, whether that line is free or engaged. The invention is described as applied to a two-wire system in which the selectors and connectors are controlled by quickrelease and slow-release relays, no side-switches being used. Subscriber's impulse - transmitter. During each rotation of the impulse-transmitter Nu, a contact 9 short-circuits the subscriber's instruments, thus removing their resistance from the line. Preliminary selector. When the subscriber removes his receiver, his line relay R completes the circuit of the actuating-magnet D<o>, which rotates the selector until its wipers find an idle group selector GW<1>, whereupon the cut-off relay T is energized over contacts k<1>, 14, resistances 5, 4, and contact 3. The relay T cuts off the line relay R and magnet D<o>, and short-circuits its high-resistance winding 6 over contact k, thus marking the line as engaged. Relay repeater. The calling line is thus supplied with current over the relay A, which closes at a contact 11 the circuit of a slow-release relay V<1>, which remains energized throughout the connexion. The relay V<1> (1) by attracting. its armature 15, disconnects the release magnet M and energizes a relay J over the normal switch contact k<1>, and (2) connects at 16 the battery G to the test relay P, vertical magnet H, meter relay ZR, &c. The relay J locks up over the armatures 18, 21, 65, so as to be independent of the contact k<1>, and, by attracting its armatures 19, 20, disconnects the condensers 7, 8 from the wipers o<1>, o<2>. The relay J remains energized until the connector has been set on the line wanted, whereupon the relay J<1> opens its locking - circuit as described later. Injurious effects due to the discharges of the condensers 7, 8 during the transmission of the impulses are thus prevented. First selector. During the interruptions of the line circuit produced by the impulse-transmitter, the relay A releases its armature 11, but the relay V<1> remains energized. The circuit of the vertical magnet H is at first closed over armatures 22, 20, relay V<2>, armatures 11, 12, and resistance 13, but the excitation of the slow-release relay V<2> substitutes a resistance 25 for the resistance 13, the relay V<1> being also kept energized over the resistance 25. During the pause following the interruptions, the relay V<2> de-energizes and closes the circuit of the rotary magnet D, which rotates the selector until its wipers find an idle second selector, when the test relay P receives current over a relay C, Fig. 2, and switch contact k'. The relay P cuts off the rotary magnet D, shortcircuits its high-resistance winding 27, thus marking the lead as engaged, and, by attracting its armatures 22, 28, disconnects the vertical magnet H and resistance 25, substituting for them the vertical magnet H<1>, Fig. 2, and relay S of the second selector. Second selector. The relay C locks up over its armature 29 and connects the battery to the vertical magnet H', which is energized during the next set of interruptions over the lead a<2>, armatures 22, 20, relay V<2>, armatures 11, 12 and thence at first over the resistance 13 to ground, but after the excitation of the relay V<2> over the armature 28 and relay S to ground. The relay S may be of the slow-release type, but it is preferably arranged so that it is kept energized during the interruptions in the circuit of the magnet H<1> by a weak current which flows through the relay Y', armatures 11, 12, 28, and 35. During the pause following the interruptions, the relay Y<2> de-energizes and opens the circuit of the relay S, thereby energizing the rotary magnet D', which rotates the selector until its wipers find an idle connector, whereupon the test relay P' receives current over a relay C<1> and switch contact k<7>. The relay P<1> cuts off the rotary magnet D<1>, short-circuits its high-resistance winding 33, thus marking the lead as engaged, and by attracting its armatures 34, 35 disconnects the magnet H<1> and relay S, substituting for them the leads a', b<3> of the connector. The relays C, P<1> remain energized throughout the connexion, the other relays and magnets being disconnected. Connector. The relay C<1> locks up over its armature 36 and by means of its armature 37 . connects the battery G to the vertical and rotary magnets H<2>, D<2>, and to a relay J' which is energized over the armature 47 and switch contacts k<7>. The relay J<3> locks up over its armature 42 so as to be independent of the contact k<7>, and completes at 43 the circuit of a slow-release relay V, which by means of its armature 40 connects the relay S<1> to the lead b<3>. At this stage the relays C', J<3>, V are all energized. When the relay A, Fig. 1, releases its armature 11 during the third set of interruptions, the vertical magnet H<2> is consequently energized, the circuit passing from the battery G over the armature 37, magnet H<2>, lead a<3>, armatures 34, 22, 20, relay V<2>, armatures 11, 12, and thence at first over the resistance 13 to ground, but after the excitation of the relay V<2> over the armatures 28, 35, 40 to the relay S<1> and ground. The relay S' is kept energized during the interruptions of this circuit in the same way as the relay S of the second selector was. When the impulses cease, the relay S' closes at 48 the circuit of a change-over relay J<2> over the switch contact k<9>. The relay J<2> locks up over its armature 50 so as to be independent of the relay S', substitutes the rotary magnet D<2> for the vertical magnet H<2>, prepares at 51 a circuit for the ringing-relay L, and disconnects at 41 the relay J<3>, which, however, remains energized until the relay S<1> is again energized by the last set of impulses. At this stage, the relays C<1>, J<2>, J<3>, and V are all energized. The last set of impulses are repeated as before to the rotating magnet D<2>, and during this time, the relay S' interrupts the circuit of the relay J', which de-energizes, but maintains that of the relay V over the armature 47. When the impulses cease, the relay S' finally opens the circuit of the slow-release relay V, and prepares at 52 that of the test relay P<2>. Disconnexion of repeater. The release of the armature 40 of the relay V connects the battery G over the switch-contact k<8> and choking-coil D<r> to the leads b<3>, b<2>, thereby energizing the relay J<1>. Fig. 1, which locks-up over its armature 21, prepares at 64 the circuit of the metering-relay ZR, and opens the holding-circuit of the relay J. The armatures 19, 20 are thus released and connect the condensers 7, 8 direct to the wipers o<1>, o<2>, and the armature 20 finally opens the circuit of the relay V<2> so that no further impulses can be sent to the selectors or connectors before the release of the connexion. Busy test and busy signal. If the line wanted is busy, the relay P<2> is not energized, and the slow-release relay V completes at 46 a circuit for the release magnet M<2> over the armatures 37, 41, 52, 56, and 46 and switch contact k<9>. A winding 53 of the differential relay J<2> is simultaneously energized, and releases the relay J<2>. When the connector has released, the contact k<7> is again closed, and earths the relay J<3>, which again energizes the relay V, thereby connecting a buzzer device Su over the condenser 55 and armature 40 to the calling line. The group selectors are released when the subscriber hangs up as described later. Supply and control of ringing-current. If the line wanted is free, the relay P<2> is energized over the armatures 37, 41, and 52, and shortcircuits its high-resistance winding 57, thereby marking the line as engaged. By the attraction of the armatures 58, 59, the called line is momentarily connected over the attracted armature 44, 45 direct to the ringing-generator Q, but as soon as the relay V has had time to deenergize, the called line is connected to the generator Q over the armatures 60, 61 of the intermittently-energized ringing-relay L. The calling subscriber is informed that a call is being made by current from the buzzer Su which at first flows over the condenser 55 and armature 40, and afterwards over the armature 62 of the ringing-relay L. When the called subscriber replies, current flows over his line through the choking-coil Dr and a relay Y, which by attracting its armature 63 maintains the test-relay P<2> energized but opens the holding-circuit of the relay J<2>, which therefore disconnects the ringing-relay L. Talking circuit and supply of microphone current. The relay Y, by attracting its armature 39, continues the speaking lead a<3> over armatures 39, 60, 44, and 58 to the wiper o', the lead b<3> being connected over armatures 40, 61, 45, 59 to the wiper o<8>. The called subscriber is supplied with current through the choking- coil Dr and relay Y, and the calling subscriber over the coils of the relay A, Fig. 1. Metering calls. The excitation of the relay Y, when' the called subscriber replies, earths the lead a<3>, thereby energizing the metering-relay ZR, Fig. 1, the circuit of which has been prepared by the relay J'. The relay ZR shortcircuits the resistance 5, thus increasing the current in the test lead c' sufficiently to energize the meter magnet Z, which is connected in parallel with one winding of the cut-off relay T. The relay ZR also opens at 65 the circuit of the relay J<1>, so that during a conversation there are no branch ci