Patent GB-181826-A (GB)
Title: Electromechanically controlled telephone system
IPC: H01H67/06
Filed: 1921-03-19
Abstract: 181,826. Baron, H., (Aldendorff, F.). March 19, 1921. Automatic exchange systems.-The customary group selector, which performs successively a numerical and a hunting operation, is replaced by a purely numerical selector having only ten sets of terminals, which are connected to the bank terminals of finding-switches in the different divisions of the next switching stage. For example, a call arriving over a call-finder CF, Fig. 10, is extended by a selector GS, which, in response to the hundreds impulses, selects one out of ten trunks, leading to the different hundreds divisions of the exchange, and the selected trunk is sought by finders GF of quick-acting type associated with the final switches WS of the wanted hundreds division. In the system described, the connection CF, GS, GF, WS is of a transitory character, serving to control simple hunting switches CC. TC, WC, which establish the talking connection. All the selectors employed are of the uni-motional kind, of rotary or panel type. Connection is made with a calling line by a quickacting finder CF, which has previously been connected by an associated switch PT with an idle slow-acting finder CC. The hundreds impulses operate the selector GS to select a trunk to the wanted division of the exchange and to set in action the finders GF of this division, one of which fastens on the incoming call. A link circuit AF, ST connects the finder GF to a preselected idle connector WC. The tens and units impulses operate switches in the marking-set WS to pick out tens and units marking wires. In the meantime, as soon as the hundreds impulses arrive, or it may be earlier, the slow-acting finder CC is started, and when it reaches the calling line a stopping circuit is closed which extends through wipers of the switches CC, PT, CF. A selector TC associated with the finder CC then hunts for the preselected connector WC. A switch associated with the selector TC, and which was operated by the hundreds impulses at the same time as the selector GS, renders the test circuit of the selector TC effective only when it reaches the group of connectors belonging to the wanted hundreds division. When the selector TC reaches the terminals of the preselected connector WC a stopping circuit is closed which extends through wipers of the switches ST, TC, PT, GS, GF, AF. As soon as the units impulses arrive, which may be before or after the selector TC has completed its operation, the connector WC is set in action to hunt for the line designated by the marking-set WS. Just before the connector reaches the group of ten lines to which the wanted subscriber belongs, a preparatory circuit is closed through the selected tens marking wire and through wipers of the switches WC, ST, AF, WS, and when it reaches the wanted line a similar stopping circuit is closed through the selected units marking wires. The temporary conrection is then released; the switches GS, WS are restored to normal; the switches- PT, ST are advanced to preselect idle trunks; the switches CF, GF, AF, being of the no-normal type, are left in the position to which they were set. The testing and ringing of the wanted line are performed bv the connector WC. After conversation the switches TC, WC are restored, but the finder CC is left in the position to which it was set. There may be ten of each of the talking switches CC, TC, WC and two or more of the transitory switches CF, GS, &c. for every 100 subscribers. In addition there is a single switch CJ, Fig. 2, and WJ, Fig. 9, for every 100 calling or called lines, to ensure that only one finder CC or connector WC can be operated at a time. Specifications 20943/21 and 7332/22 are referred to. Operation of the quick-acting call-finders CF<1>, CF<2>, Fig. 2. The line relay AR of a calling line S<1>, Fig. 1, (loses a circuit 3 which energizes a relay TR only sufficiently to close its contacts 6, 596. The contact 6 completes a circuit 8 for the stepping magnets Df, Df<2> of the finders CF<1>, CF<2>. These switches are of the no-normal type and have five sets of wipers, each serving 20 lines and provided with a separate test relay T<1>, T<2> &c. As soon as a test wiper, say 19, engages the teiminal of the calling line, the corresponding test. relay T<1> becomes energized in series with a relay S' and the left-hand winding of the relay TR. The relay S<1> stops the finder and opens the initial feed circuit of the five test relays, and both relays S<1>, T<1> short-circuit their high-resistance windings, increasing the current in the circuit 16 so that the relay TR becomes fully energized. The relay TR locks itself and opens the stepping circuit S. The calling line has now been connected by the finder CF<1> to a selector GS<1>, Fig. 4, and, moreover, the trunk CF<1>, GS<1> has previously been connected by a switch PT<1>, Fig. 1, to an idle trunk connecting a call-finder CC<1> with a selector TC<1>, Fig. 3. Operation of the selector GS<1>, Fig. 4, and marking switch GSI, Fig. 3, bv the hundreds impulses. At each impulse the line relay AR, Fig. 1, closes a circuit 31, Fig. 4, 29, S<1>, Fig. 2, T', 19, 16, 37, Fig. 1, 38, 41, Fig. 2, 43, 45, 48, Fig. 4, V<1>, Fig. 2, 50, 51, to the stepping magnet HM<1>, Fig. 4, of the switch GS<1>, and a branch of this circuit passes through 50, 53, 54, Fig. 1, 57, 58, to the stepping magnet Dg<1> of the switch GSI associated with the selector TC<1>. At each impulse the circuit of the relays S<1>, T<1>, TR is opened, but these relays are of the slow-release type and hold up their armatures. The slowrelease relay V<1> is energized at the first impulse and remains energized as long as impulses are passing and keeps the impulse circuit closed at its contact 60 after the off-normal contact 31 of the selector GS<1> has opened. The selector GS<1> extends the connection to terminals in the banks of the finders GF<1>, GF<2>, Fig. 7, associated with the marking-sets WS<1>, WS<2>, Fig. 9, serving the group of 100 lines to which the wanted line belongs. Operation of the slow-acting call-finder CC<1>, Fig. 1. A switch CJ, Fig. 2, common to the group of 100 calling lines and having a set of terminals for each quick-acting finder, is set in rotation by the relay V<1> and is brouglit to rest on the terminals of the successful finder CF<1> by the energization of relay Tc in series with relay J<1>. The relay J<1> connects battery over the circuit 73, 78 to the wire 80, so that if the switch PT<2> is resting on the same trunk CC<1>, GS<1> as the switch PT<1>, the relay Ep<2> is energized and causes the switch PT<2> to move forward to the next idle trunk. A branch of the same circuit extends through 80, 99, 100. 101, 103 to the relay F<1>, which closes the stepping circuit of the finder CC'. When the test wiper 135 reaches the terminal of the line occupied by the finder CF<1> the relays Pc<1>, Fig. 1, and P<1>, Fig. 2, are energized in a circuit 123, Fig. 2, 126, 127, 128, 130, 131, 122, Pc<1>, 135, 137. 138, 140, 142, 143, P<1>, 146. This circuit, it will be seen, includes wipers of the switches CC<1>, PT<1>, CF<1>, and terminates at both ends through wipers of the common switch CJ, which ensures that only one of these controlling operations can proceed at a time. The relay Pc<1> stops the finder CC, and energizes the relay Tc', which locks itself up. The relay P' unlocks the relays J', Jc and thus renders the switch CJ available for other service. Operation of the finders GF<1>, GF<1>, Fig. 7, to connect an idle marking-set WS<1> or WS<2>, Fig. 9, to the terminals engaged bv the selector GS<1>, Fig. 4. The finders GF<1>, GF<2>, like the finders CF<1>, CF<2> are of the type in which five sets of brushes search simultaneously. The relay V<1>, Fig. 2, energized a slow-release relay W<1>, Fig. 4, and the de-energization of the relav V<1> following the transmission of the hundreds digit closes an interrupter circuit W<1>, 157, 159, 160, 161, 162, 164, 166, 168, Fig. 7, 169, 172, through the stepping magnets D, D' of the finders GF<1>, GF<2>. When a test wiper, say the wiper 182 of the switch GF<1>, reaches the terminal engaged by the switch GS<1> it completes a circuit W<1>, 157, 159, 160, U<1>, 177, 179, 180, 182, T<1>, 188, S, 192, 194, energizing the relays U<1>, Fig. 4, and T', S, Fig. 7. The relay U' extends the impulse circuit 45 to the relay JR<1>, Fig. 9, of the marking- set WS<1>. The relay S opens the stepping circuit and the relays T', S short-circuit their high-resistance windings. Operation of the link circuit AF<1>, ST<1>, Fig. 6, to connect the trunk GF<1>, WS<1>, to an idle connector WC<1>, Fig. 8. The relay S, Fig. 7, closes a circuit 214, 216 to energize the relay R', Fig. 6, or if the link circuit AF<1>, ST<1> is already in use the relay R<2> of the link circuit AF<2>, ST<2> is energized instead. The relay R' closes the circuit of the stepping magnet Df<1> of the switch AF'. When the wiper 226 reaches the terminal individual to the switch GF<1> the relays O<1>, Tf<1> are energized in a circuit 229. The relay Tf<1> stops the switch AF<1>, de-energizes relay R<1>, energizes relay Ps', and opens the circuit of the stepping magnet Ds' of the switch ST<1>, which normally stands on the terminals of an idle connector, assumed in the present case to be the connector WC<1>, Fig. 8. If the switch ST<2> is at this time standing on the terminals of the same connector, a circuit is closed by the relay Tf<1> through the wipers 235, 239 to energize the relay Ps<2>, which energizes the magnet Ds<2> to move the switch ST<2> to the terminals of the next idle connector. Operation of the selector TC<1>, Fig. 3, to find the pre-selected connector WC<1>, Fig. 8. The relay O<1>, Fig. 6, energizes the relay R', Fig. 1, in a circuit 248 which extends through wipers of the switches GF<1>, GS<1>, PT<1>. The relay R<1> energizes the stepping magnet D<1> of the selector TC<1>. As the wipers of the switch TC<1> pass from the