Patent GB-191316538-A (GB)
Title: Improvements in Automatic and Semi-automatic Telephone Systems.
Filed: 1913-07-18
Granted: 1914-07-16
Abstract: 16,538. Siemens & Halske Akt.-Ges. Sept. 10, 1912, [Convention date]. Automatic and semi-automatic exchange systems.-The impulses transmitted by the calling subscriber or operator build up a temporary connexion to the wanted line through group selectors and a connector, and a talking-connexion is then automatically established over a parallel path which includes fewer or simpler switches than the temporary connexion. For instance, the calling subscriber I, Fig. 1, is connected by non-numerical switches AS', VW<1> to an idle set of junction terminals of the series A, and is further connected by a switch S and numerical switches IGW, IIGW, LW to the wanted line II. The line II is then connected by non-numerical switches AS<2>, VW<2>, which are the same that would be used by the subscriber II in originating a call, to an idle set of junction terminals of the series B. Finally, the talking-connexion between the A and B junctions is completed by a two-co-ordinate junctionconnector RW, which is actuated by impulses sent over the path IGW, IIGW, LW, AS<2>, VW<2>, B by an impulse-transmitter ZG. The number dispatched by the transmitter ZG is a two-digit figure determined by the setting of the switch S on the junction A, and corresponds to that junction. As soon as the talking-connexion is completed the switches S, IGW, IIGW, LW are released for further service. It is possible to have only a single numerical selector RW in the final connexion owing to the fact that the number of junctions is only a small fraction of the number of subscribers, and also because the switches RW may have more than the usual number of terminals in their banks, there being no necessity to adhere to the decimal system in numbering the junctions. In systems involving a greater number of subscribers the talking-connexion may be through two numerical switches, either or both of which are between the A and B junctions. The junction-connectors, instead of being associated with the B-junctions and operating backwardly, as in Fig. 1, may be associated with the A-junctions, as shown at FW, Fig. 1<a>, the impulse-sender ZG being connected with the B-junctions by an auxiliary switch S'. The following paragraphs describe a connexion made according to the scheme shown in Fig. 1. Operation of the non-numerical switches AS', VW<1>, Fig. 4, and S, Fig. 6. When the subscriber I lifts down his receiver, his call-relay R<1> is energized in series with a pilot relay A<1>, which closes the circuits of the rotary magnets D', D<2> of the switches AS<1>, VW<1>. When the call-finder AS<1> comes to the terminals of the calling line it is brought to a stop by the energization of a relay P<1>. The cut-off relay T' in the same circuit is not energized at this stage. The preliminary selector VW<1> has some of its terminals connected to junctions of the series A, Fig. 1, and others to junctions of the series B. The test lines 13 of the A-junctions are connected to the third row of terminals of the switch VW<1>, while those of the B-junctions are connected to the fourth row, and since under present circumstances the test relay P<2> is connected to the third wiper, the switch VW<1> selects an idle junction of the A series. The energization of the relay P<2> stops the switch VW<1>, renders the selected junction non-selectable to other switches by closing the contact 16, and completes the circuit of a relay C'. The relay C' locks itself independently of the relay P', short-circuits the relay P<1> so as to energize the cut-off relay T', and switches the line forward at the contacts 25, 26. The impulse relay J<5>, Fig. 5, is now energized over the calling line and closes the circuit of relays V5, A<5>. The relay V<5> energizes a relay V<6>, which remains energized until the connexion is released, and the relay A<5> connects up the rotary magnet D' of the switch S. When this switch comes to the terminals of the junction A, Fig. 5, it is stopped by the energization of a relay P', which shortcircuits its left-hand winding and locks itself up under control of the relay J<8>, which is energized over the contacts 41, 42. A slow-acting relay V<7>, Fig. 5, which was energized in series with the relay P<7>, disconnects the relays V', A<5> and locks itself up under control of the relay J<5>. The circuit of the relays V<6>, P<2> is now maintained at the contact 46. Establishment of the temporary connexion by the switches IGW, IIGW, LW, Figs. 6 and 8. The first set of line-interruptions from the subscriber's impulse-transmitter controls the relay J<5>, which repeats them to the relay J<8>, Fig. 6, which controls the vertical magnet H<8> of the first selector IGW. At the termination of the series, a relay V<8>, which was also energized by the relay J<8>, de-energizes and opens the circuit of a magnet St, which moves the side switch 44, 53, &c. to its second position, in which the rotary magnet D<8> is brought into circuit. When an idle second selector IIGW is found, the rotary movement is brought to a stop by the energization of a relay P<8>, which causes the side-switch to move to its third position by deenergizing the magnet St. The selected line is now marked non-selectable by the side-switch arm 53, and the circuit of the relay J<8> is switched forward to the relay J", Fig. 7, which energizes the relay V<11>. The second set of interruptions is repeated by the relays J<5>, J" to the vertical magnet H<11> of the second selector IIGW. At the first vertical step the original circuit of the relay V<11> is opened at the normal contact 58, but the relay is kept energized by impulses through its second winding 61. At the termination of the series, the relay V<11> deenergizes and completes the circuit of the rotary magnet D<11>. When an idle connector LW is found, the rotary movement is stopped by the energization of a relay P<11>, which locks itself by opening the short-circuit across its left-hand winding, marks the selected line non-selectable by short-circuiting its right-hand winding, and switches the impulse-circuit forward to the connector relay J<12>, Fig. 8. The relay J<12> energizes the relays V<12>, V<13>, V<14>. The third set of interruptions is repeated by the relays J<5>, J<12> to the vertical magnet H<12> of the connector LW. At the first vertical step the original circuit of the relay V<12> is opened at the normal contact 76, but the relay is kept energized by impulses through its second winding 74. At the termination of the series the relay V<12> de-energizes and connects the rotary magnet D<12> in place of the magnet H<12>. The fourth set of interruptions controls the magnet D<12> to rotate the switch LW to the terminals of the wanted line, and at the termination of the series the relay V<13> is deenergized, its original circuit having been opened at the rotary normal contact 83. Busy test and release. The de-energization of the relay V<13> is followed by that of the relay V<14>, but in the momentary interval a circuit is closed for the relay P<12>, and if the wanted line is disengaged this relay becomes energized over the contact 88 and locks itself up by means of its second winding. If, however, the wanted line is busy, the relay P<12> fails to become energized, since either the contact 88 is open, or the wire 87 is connected to ground at the contact 89 of another connector. In this case the relay J<8>. Fig. 6, is open-circuited at the contact 78 and de-energizes the relay P', which causes the release of the connexion as described in a later paragraph. Operation of the called subscriber's non-numerical switches AS', VW<2>, Fig. 9. The energization of the relay P<12>, when the wanted line is found to be disengaged, energizes the relays R<2>, A<2>, Fig. 9, in series with the relay J<8>, Fig. 6. The relays R<2>, A<2> initiate the operation of the switches AS<2>, VW<2>, which connect the wanted line to an idle junction B, Fig. 1, in just the same way that the calling line was connected by the switches AS<1>, VW<1> to a junction A, the only difference being that when the switch AS<2> has found the line of the wanted subscriber the relays V<2>, U<2> are energized, and the test relay P<4> is therefore connected to the fourth instead of the third wiper, so that a junction of the B-series instead of the A-series is selected by the switch VW<2>. When both the switches AS<2>, VW<2> have completed their operations, the relay C<2> is energized and switches the relay V<2> in series with the relay J<15>, Fig. 10, of the junction B. The relay J<15> energizes the relay V<15>. Completion of the talking connexion by the junction connector RW, Fig. 10, under control of the impulse-sender ZG, Fig. 6. In response to the second, third, and fourth sets of impulses, the relays J<8>, V<8>, Fig. 6, operated, just as in the case of the first set, to move the side-switch from the third to the sixth position, from which it is moved automatically, the contact 105 being closed, to the seventh position. Impulses now pass through the side-switch arm 52 and a magnet D<9>, which rotates an arm 108 till it reaches the contact connected to battery by the arm 109 of the switch S, whereupon the impulse circuit is opened by the relay P<8>. The relay P<8> also de-energizes the magnet St, which moves the side-switch to its eighth position. The magnet D<10> is now brought into action and rotates the arm 110 till it is stopped in the same way by the relay P<8>, which advances the sideswitch to its ninth position. The arrangement of the contacts engaged by the arm 109 and their connexion to the switches 108, 110 are such that the two series of impulses which pass through the magnet D<9>, D<10> in the above operations correspond to a two-digit numeral representing the particular junction A to which the switch S has connected itself. The same numbers of impulses must be passed through the vertical and rotary magnets of the junction connector RW, Fig.