Patent GB-190628091-A (GB)
Title: Improvements in or relating to Telephone Exchange Systems.
Inventor: CLEMENT EDWARD EDMUND
Filed: 1906-12-10
Granted: 1907-11-07
Abstract: 28,091. Clement, E. E. Dec. 10. Telephone systems. -Relates to an automatic exchange telephone system in which earth connexions at the subscribers' station are avoided, each subscriber signalling and controlling the exchange apparatus merely by making and breaking the metallic circuit. The exchange switches are controlled by relays of two types, the movement of the e switches being effected by ordinary quick-acting relays, and the circuits of these switches being prepared by a pair of sluggish relays, preferably solenoids, which respond readily so as to be actuated by short impulses, but are not quickly deenergized. By this means, if groups of short impulses separated by pauses of some e length are sent from-the substation, the e sluggish relays remain energized while the short im pulses actuate the selector or connector switch ; but during the pause between each set of impulses the relays have time to operate and thus prepare the working p a r t of the apparatus for the next series of short impulses. No side switches are e used in the system described, the changing of the different local circuits being effected by relays or by the movements of the switch spindles. The selector and connector switches are so constructed that the rotary movement of the switch spindle takes place before the vertical movement. Figs. 3, 4, 5, and 6 are to be read in conjunction with one another; Fig. 3 shows the sub-station apparatus, and the exchange end of the subscriber's line. The springs o, o<1> of the impulse sender normally complete the line circuit, but are separated by the pins o<2> on the hand-wheel o<3> during the return movement of the latter, after having been set to the desired number. The line-wires 2, 3 are earthed through the impedance I and a quickacting relay S, which controls the circuits of the sluggish relays A<1>, B'. When the relay S is energized, current passes from the battery B through the wire 22, contacts s, s<1>, and solenoid B<1> to earth. The attraction of the core b<5> closes contacts b, b<1> and completes the circuit of the solenoid A' from the battery B, wires 22, 30, contacts b<1>, b, wire 23, contacts s<2>, s<4> to the solenoid A<1> and ground. As this circuit is broken when the armature s<2> is attracted, and as the solenoids A', B' respond to rapid impulses, it will be seen that both solenoids are energized during the passage of these impulses, but that during the succeeding pause only the solenoid B<1> is energized, and the core a<5> falls back, sending a momentary impulse over the trunk line 5 which prepares the path for the next group of short impulses, as will be seen later. The solenoid B<1> remains energized, until the subscriber hangs up his receiver, and the movement of its core is used to set in action the re'ease magnets. The operation of the system is as follows :-The calling subscriber removes his receiver, thus closing the line circuit through the relay S, energizing the solenoid B', and breaking the circuit of the solenoid A'. The subscriber then sets his impulse sender to the " thousands " number of the wanted subscriber, and the sending of these impulses intermittently energizes the relay S so as to energize both relays A', B<1>, as well as sending current impulses from the battery B through the wires 22, 30, springs b<1>, b<2>, wire 23, contacts s<2>, s<3>, and trunk wire 4 to the springs m, m<1>, Fig. 4, and relay S<1> of the first selector. First selector. The relay S<1> in turn energizes the rotary magnet K to step round the switch spindle Z, the circuit of the magnet K passing from the battery B through the wires 44, magnet K, contacts f<4>, f<5>, and contacts s<5> to ground. The wipers z<1>, z<2>, z<3> are thus brought into line with the groups of contacts leading to second selector switches of the desired thousand. The pause at the end of the group of impulses causes the solenoid A' to be de-energized ; the core a<5> momentarily closes the contacts a, a<1>, a<2>, thus sending a single cutrent impulse from the battery B through the wire 22, contacts s, s', wires 24, 28, contacts a<2>, a', wire 32, trunk line 5, springs m<4>, m<3>, Fig. 4, to the grounded relay D' of the first selector. The attraction of the armature d' momentarily completes the circuit of the test relay F, and this in turn momentarily completes the circuit of the vertical magnet L from the battery B through the wires 45, 51, contacts d<2>, d<3>, magnet L, and contacts f<2>, f<1> to ground. The spindle Z is thus raised one step, closing the contacts z<4>, z<5>, and bringing the wipers z<1>, z<2>, z<3> on the first contacts leading to a second selector. If the test contact on which the wiper z<3> rests is busy or grounded, the relay F remains energized by current from the battery B through wire 45, magnet F, contacts m<6>, m<7>, wire 43, and test wiper z<3> to the grounded test contact, and the circuit of the vertical magnet L remains closed through the interrupter V, Fig. 5, wire 48, contacts d<4>, d<3>, magnet L, and contacts f<2>, f<1> to ground. The interrupter thus causes the switch to step up vertically until an ungrounded test contact is found, whereupon the relay F is de-energized, and the circuit of the magnet M is completed from the battery B through the wire 47, contacts z<5>, z<4>, magnet M, and contact f, f<1> to ground, The energizing of the magnet M disconnects the relays D', S', and connects the trunk lines 4, 5 to the wires 6,7, thus continuing the line-wires through to the second selector, and at the same time connecting the back release relay X through the contacts m<7>, m<8> to the test wiper z<3>. This relay X is low wound so as not to respond when the wiper of some other switch passes over a multiple of the contact upon which the test wiper z<3> rests. Second selector. The calling subscriber being now connected to a second selector sends in a set of impulses operating the relay S<2>, Fig. 5, controlling the rotary magnet K' and thus bringing the wipers z<9>, z<10>, z<11> in line with contacts of connector switches of the desired hundred. The single impulse coming over the wire 9 operates the relay D<2>, thus raising the spindle one step as before, and bringing the wipers to rest on the first set of contacts leading to a connector switch of the desired hundred. The spindle continues to step up until the test wiper z<11> finds an idle contact, when the relay F<1> is de-energized and the next relay on the left energized, thus disconnecting the relays D<2>, S<2>, continuing the wires 8, 9 to the connector switch, and connecting in the back release relay X'. Connector. The calling subscriber then sends in the third set of impulses, operating the relay S<3>, which completes the circuit of the rotary magnet K<2> from the battery B through the wires 94, 98, magnet K', contacts z<24>, z<23>, wire 92, contacts m<26>, m<25>, and contacts s<11>, s<12> and d<6>, d<17> to ground. The magnet K<2> brings the wipers z<17>, z<18> in line with a row containing the desired line. The single impulse coming over the wire 13 momentarily operates the relay D<3>, which momentarily closes the circuit of the vertical magnet L' from the battery B through the wire 94, magnet L', contacts z<19>, z<21>, wire 96, and contacts d<14>, d<15>, s<14>, s<13> to ground. The magnet L' raises the spindle one step, thus opening contacts z<24>, z<23> to disconnect the magnet K', but closing contacts z<22>, z<23> so as to connect the magnet L' in place of the magnet K<2>. The calling subscriber then sends in the fourth set of impulses, operating the relay S<3> which actuates the magnet L' to bring the wipers z<17>, z<18> on the contacts of the desired line. After the first of these impulses is received, the contact z<9>, z<21> is opened, removing the magnet L' from the control of the relay D<3>, and in its place connecting the relay M'. The single impulse coming over the wire 13 then operates the relay L<3>, which completes the circuit of the magnet M' from the battery B through the wires 86, 87, 88, magnet M', wire 95, contacts z<20>, z<21>, wire 96, and contacts d<14>, d<15>, s<14>, s<13> to ground. The attraction of the armature m<23> completes a locking circuit through the magnet M'. The single impulse operating the relay D<3> also momentarily places the relay X' in a test position by the following paths : from the battery B through the wire 86, contacts d<13>, d<12>, wire 85, relay X', and wire 93 to the test wiper z<15>. Busy tet. If the desired line is busy, the test contact is grounded and the very sensitive relay X<2> responds, energizing the release magnet W' and sending a busy signal to the calling subscriber, who then hangs up his receiver, thus setting in action the successive release circuits described later. Ringing current. The energizing of the relay M' connects the wires 14, 15 through to the wipers Z<17>, z<18>, and at the same time opens the contact m<26>, m<25> in the circuit of the magnet L', and closes the contact m<25>, m<24> in the circuit of the ringing relay Y. The calling subscriber again sends in a series of short impulses, operating the relay S<3> which in turn actuates the ringing relay Y to connect the generator G to the called line. Release. The release of the switching-mechanisms is controlled by the calling subscriber. During conversation, the relay S is energized so that the core of the solenoid B', Fig. 3, is raised, while that of the solenoid A' is lowered. - When the subscriber hangs up his receiver, the relay S is de-energized, whereupon the solenoid A' at once draws up its core, while the core of the solenoid B' commences to fall, and as soon as it reaches its normal position the battery B is connected to both sides of the trunk circuit through the contacts a<4>, a<3>, b<4>, b<3>, b<2> and wires 21, 31. After it has assumed its normal position, the contacts b, b<1> are opened, thus de-energizing the solenoid A', and consequently