Patent GB-263176-A (GB)
IPC: H04Q3/42
Filed: 1926-12-17
Abstract: 263,176. Barnay, A. Dec. 18, 1925, [Convention date]. Automatic exchange systems. -In a system using markers which apply potential to numerically-selected steering wires, each wire marks a plurality of non-consecutive marking contacts, the speed of the selector, which begins to advance after the receipt of the first impulse, being so related to that of the impulse sender that the marking wiper and the marking potential are never simultaneously on a marking contact except in the case of that contact which is finally marked. The principle of the invention is shown in Fig. 1 in which four steering wires 4 - - 7 are connected to ten marking contacts I - X of the selector driven by a magnet M, the first wire 4 being connected to contacts I, V, IX, the second wire 5 to contacts II, VI, X. and so on. The wires 4 - - 7 are grounded successively and cyclically by the re. ceived impulses, and the speed of the selector is such that in sending, for example, five impulses the marking wiper 1, which is connected to a stopping relay 3, has left contact II before the wire is grounded for the second time by the last impulse. Fig. 2 shows a marker arranged or this principle for use with a group selector whilst Fig. 3 shows one for use with a connector Group selector marker. Four steering wires are connected to ten groups of marking contacts I - - X, Fig. 2, as in the arrangement shown ir Fig. 1, the wires being grounded successively and cyclically by a chain of four pairs of relays 11. 20, 21, 24, &c. The line relay 8 and release relay 9 respond when the switch is taken intc use, and when the relay 8 relapses in response to the first impulse, relay 11 is energized, locks in series with relay 20, grounds the first steering wire, and closes a circuit for the stepping mag net M, which circuit however is immediately opened by a relay 3 which is energized over wiper 1, and the grounded first steering wire. At the second relapse of relay 8, the second chain relay 21 is energized over contact 22 and locks in series with relay 24, which unlocks the first relay pair 11, 20, and prepares a circuit for the third pair 27, 29. Ground is now removed from the first steering wire and applied to the second steering wire, with the result that the relay 3 deenergizes and the stepping magnet M is energized and begins to advance the switch wipers. The received impulses continue to energize the relay pairs cyclically, the fifths impulse for example re-energizing the first pair 11, 20 which unlock the fourth pair 31, 33, and so on. On the cessation of the impulse series, relay 39 relapses, and when the wiper 1 arrives on the first contact of the marked group of lines, relay 3 is energized over the grounded steering wire and opens the first circuit of the magnet M. A hunting circuit 41, 40. 1 is now closed for the magnet M. which is opened at contact 25 when the test relay 44 locks energized on the test wiper 45 engaging the test contact of an idle line. In a modification, onlv the first contacts of each group are marked by the steering wires, the remaining marking contacts of the wanted group being connected to the earthed steering wire bv an additional relay which is energized on the cessation of the impulse series. Single two-step relays may be used in place of the relay pairs 11, 20. &c. Connector marker, Fig. 3. In this the same chain of relays and group of steering wires are used twice in succession, first for marking a wanted group in response to one digit and then for marking a particular line in this group in response to a second digit. The connector is of the kind described in Specification 233,339 having two wiper sets for odd and even tens groups respectively. When the switch is taken into use, relays 8, 9, 52 energize, the latter switching the steering wires on to the group marking contacts 1DI, II, DIII, IV, &c. The first impulses of the first digit energize the relay pairs 11, 20, 21, 24, &c. to mark odd and evens tens groups, a relay 58 being energized over armature 61 or 62 at the end of the digit to connect up the lower wiper set if the tens digit is even. The magnet M is energized when ground is removed from the first steering and when the marking wiper 1 reaches the first line in the wanted group, relay B energizes, opens the circuit of the magnet M and de-energizes the chain relays, after which a short-circuit is removed from a relay 69, which locks up and de-energizes relay 52. Relay 52 transfers the steering wires to the units marking contacts UII, III - - X, and connects the first (previously the tens) marking contacts in each group to the other units marking contacts. The units digit causes the chain relays to mark the wanted line, and the switch to advance thereto, as described with reference to the tens digit, the relay 39 relapsing at the end of the impulse series, energizing relay 92, and closing a test circuit over relay 91 and the test wiper 64 or 65. If the called line is idle, relay 91 energizes and locks up before the response of the slow-acting relay 92, but if the line is busy relay 92 alone responds and gives a busy signal. Specifications 223,985, 235,578, and 242,594 also are referred to.