Patent GB-233339-A (GB)
Title: Improvements in or relating to automatic switching arrangements particularly for usein telephone systems
IPC: H04Q3/42
Filed: 1925-04-27
Abstract: 233,339. Barnay, A. April 29, 1924, [Convention date]. Addition to 223,985. Automatic exchange systems.-Relates to systems of the kind described in the parent Specification in which the selectors are provided with a plurality of wiper sets, a particular wiper set being connected up in accordance with the setting of a marking switch which also marks the wanted line or group of lines. The present invention describes modified arrangements of the marking switch and of the means for connecting up the correct wiper set. In some of the modifications the relays for connecting up the correct wiper set also function as stopping relays for arresting the rotation of the main switch, whilst in other modifications, described as applied to group selectors, they also function as test relays. In another arrangement the correct wiper set is directly connected up over an auxiliary arm of the marking switch. The wiper sets may be divided into groups each rotated by a separate stepping magnet, the groups of wiper sets being rotated simultaneously or in succession. In a further modification, described as applied to a small capacity system illustrated in Fig. 7, the connector is provided with plurality of wiper sets which are moved to a wanted line, or a wanted group of trunks to a distant exchange, in two stages, the marking switch being set by the first digit to control the first stage of movement, then restoring, and afterwards responding to the second digit to control the second stage. Means are also provided for restoring the marking switch and giving a busy tone if the calling party does not dial within a given period. Methods of connecting up correct wiper set. Fig. 1 shows a. group selector K3 having four wiper sets (each set represented by a single wiper 604 - - 607) and a common control wiper 125, all driven by a single stepping magnet 115. The marking switch C1 is set by the dialled impulses and marks a contact in the bank of the control wiper 125, thereby causing the group selector to stop in the position in which one of the wiper sets engages the first trunk in the wanted group of outgoing lines. The switch Cl is provided with two additional concentric rows of contacts so connected to two switching relays 90, 90<1>, that according to its setting, neither, one, or both of these relays are energized in series with the stopping relay 84 over the control wiper 125, and connect up that wiper set which stands on the first trunk of the wanted group. The group selector then hunts for an idle line therein as described in the parent Specification. A modification is shown in Fig. 2 in which the marking switch C1 is provided with an extra wiper 603 over which the appropriate wiper set is connected up. In the arrangement shown in Fig. 3, three wiper sets represented by the wipers 618 - - 620, are each allotted a separate control wiper 615 - - 617 and the marking contacts of the switch C1 are connected to the groups of contacts engaged by the different control wipers 615 - - 617, thereby allowing different numbers of trunks to be allotted to the outgoing groups. The stop relays 621 - - 623 connected to the control wipers 615 - - 617, open the stepping circuit at armatures 627 - - 629 and also at armatures 630 - - 632 connect up the appropriate wiper set. When an idle trunk in the wanted group is engaged, the energized slop relay 621 - - 623 locks up over its lower winding and a contact 64 of the test relay 61. Fig. 4 shows a further modification in which the groups of outgoing lines are arranged in vertical rows and the sets of wipers simultaneously test for an idle line. The switch comprises a common control wiper 125 and three sets of wipers 643 - - 645 each with a test wiper 640 - - 642 connected to a test relay 652 - - 654, which also acts as a wiper-connecting relay. When the wiper sets arrive at the wanted group of lines, the stop relay 637 energizes over the control wiper 125 and the marking switch arm 100 at armature 639 transfers the stepping circuit of the magnet 115 to the control of the test relays 652 - - 654, and at armatures 649 - - 651 connects the upper windings of these relays to the test wipers 640 - - 642. When one of the wiper sets engages an idle line, the corresponding test relav 652 - - 654 is energized and connects up the appropriate wiper set. If two or more idle. lines are simultaneously engaged, the first test relay connects up its wiper set and disconnects the succeeding sets. The succeeding test relays fall back on the relapse of the series relay 68, but the first test relay locks up to ground sent back by the following switch. The wiper sets may be divided into groups each driven by separate stepping magnets, the wiper sets being selected by any of the previously-described means. In the arrangement illustrated in Fig. 5, three separately-driven groups each comprising twowiper sets are provided. The marking switch C1 is provided with an additional wiper 670 over which the stepping magnets 710, 712, 714 are connected up in succession. The appropriate wiper-set is connected up by a combination of the means shown in Figs. 1 and 3, one of the stop relays 684 - - 686 being energized over the wiper 100 of the marking switch and the control wiper 701, 704 or 707 of the wiper-set associated with the wanted group of outgoing lines. One of the relays 684 - - 686 selects a particular group of wiper sets, whilst a relay 676 which remains. inert or is energized in series with the relay 684 - - 686 connects up the upper or lower wiperset in the selected group. According to a further modification several groups of wiper sets are simultaneously driven by separate stepping magnets, the common circuit of the stepping magnetsbeing opened when a wiper set engages an idle line in the wanted group, and the correct wiper set being connected up by any of the methods previously described. Operation of system, Fig. 7. This is a small capacity system in which calls are extended over a line finder having two sets of simultaneously hunting wipers, and a single-motion connector with two wiper sets and which moves to the wanted line in two stages under the control of a marking switch common to a group of links each comprising a finder and a connector. The contacts in the connector banks are arranged as described with reference to Fig. 7 of the parent Specification. When a calling subscriber P removes his receiver, the line relay 1 energizes the starting relay 4 of an idle link of a group of links the common marking switch of which also is idle. The relay 4 associates the engaged link with the common marker and closes a circuit for the stepping magnet 20 of the finder, which rotates both its wiper sets until one engages the calling line. upon which the appropriate test relay 18 or 19 energizes, opens the stepping circuit, and extends the calling line to the impulse relay 27 of the marker, over which relay-dialling tone is sent to the calling party. Relay 27 energizes a slow-release relay 29 which at armature 5<a> extends the starting wire to another group of connecting links. The calling party now dials the tens digit closing a stepping circuit for the driving magnet 33 of the marking switch. In the second and third positions of the marking switch a stop relay 42 is energized over the inner and outer contacts wiped by the arm 34, the connector control wiper 43 in its normal position, and contacts 44, 14, 45. As no group selecting movement is required, if the tens digit is 1 or 2 the relay 42 holds open the circuit of the connector stepping magnet 138 until the marking switch leaves its third position, when it relapses and closes a circuit 36, 38, 39, 40, 18, 41 for the magnet 138, which rotates the connector wiper sets until the control wiper 43 engages a contact marked by the wiper 34 of the marking switch. The circuit of the stop relay 42 is then re-completed and the connector arrested : at the same time the correct wiper set is connected up, the relay 108 remaining inert or being energized over wiper 34 and locked over its lower winding according to whether the tens digit is odd or even. The relay 42 also completes a further circuit for magnet 33 in series with a relay 60, which closes a holding circuit for relay 42. The marking switch is then restored to its normal first position, after which the relays 42, 60 relapse. Between the relapse of relays 42, 60 a relay 64 energizes, locks up, and earths the inner contact row associated with the wiper 35. The calling party now dials the units digit, the marking switch is again set, and the connector is rotated as before and arrested on the marked wanted line. When the relay 53 falls back, the relay 64 remains held, and a relay 68 is energized, and closes a series circuit 10, 17, 75, 78, 69, 76, 16, 79 for relays 73, 74, to a point between which the test wiper 47 or 50 is connected. If the wanted line is busy, relay 74 is shunted by earth on the test wire, but relay 73 responds, disconnects the calling line from relay 27, and connects it to relay 82. The marking switch restores on the relapse of series relay 29 as described later, and the relay 4 unlocks and disconnects the marking switch from the engaged connecting link. Busy tone is sent over the transformer 101, and on the calling party hanging up, release occurs as described later. If the called line is idle, both relays 73, 74 energize, the marking switch is restored and disconnected, and ringing current is sent to the called line. Upon the reply of the called party, the ring cut-off relay 107 and the feed relay 111 energize. When the calling party hangs up, relays 82, 73, 74 relapse, and relay 107 holds over its upper winding in parallel with the stepping magnet 138, which restores the connector to its normal position in which relay 107 is deenergized. In the marking switch the relapse of relay 29 de-energizes relays 64, 68, and a restoring circuit is closed for the stepping magnet 33 in series wi