Patent GB-227497-A (GB)
Abstract: 227,497. Relay Automatic Telephone Co., Ltd., and Rousseau, E. J. C. Oct. 5, 1923. Automatic exchange systems.-In a system of the kind described in Specification 142,265, in which an incoming line such as Aa is connected to a subscriber's line over three sets of inter- .mediate lines such as A1, SG1, TG1, the relay connecting units are replaced by '' bar relay switches " which term includes cross-bar switches and also switches of the kind described in Specification 225,932 in which a particular set of contacts is selected by an auxiliary coil and is afterwards closed by a " bar relay " common to a number of sets. The system shown in Fig. 1, in which the links are arranged as in Specification 142,265 is described as using cross-bar switches of the kind described in Specification 141,005. The system shown in Fig. 5 is described with reference to the other type of switch. In this system, all the secondary links from a particular switch SG go to the same tertiary switch TG, and each occupies a horizontal row therein. At the same time, each contact of a tertiary switch is connected to a different tertiarv link. With this arrangement it is possible to provide common actuating members for the horizontal rows in secondary and tertiary switches or for the vertical rows in primary and secondary switches. First system. Figs. 1 - - 4. It is assumed that as the result of the setting of an impulse recorder, the wire 2 of the incoming trunk Aa and the wire 22 of the tertiary link TT1 have been marked. Magnet OTM1 marks the incoming horizontal row of the trunk Aa and energizes the vertical magnets OLM1, OLM5, Fig. 3, belonging to the group A1 of primary links in each of the secondary switches in which the link is idle. These magnets send forward over circuits 14 - - 17, 18 &c., and back contacts of busying relays such as ILB1, Fig. 4, particular to the different secondary links, a ground to operate the marking magnet ITM1 of the vertical row belonging to the marked tertiary link. The magnet energizes a relay SS which completes a chain-testing circuit 28 to energize the relay ILM1, ILM2 &c. of the first idle secondary link to which an idle primary link of the group Al can be connected. The operation of relay (say) ILM1 energizes the link-operating magnets ILC1, OLC1, LLC1 along the selected route and the completion of circuit 31 energizes the busying relays ITB1, ILB1, OLB1. The removal of the marking from wires 2, 22, releases the magnets ITM1, OTM1 and consequently the magnet OLM1 and the relay ILM1, the connection being held by the link operating magnets which are locked to circuit 31. Second system, Figs. 5 - - 8. In response to the marking of wire 40, Fig. 6, relay OTM1 marks the incoming horizontal row of auxiliary coils ASa, ASb, &c. belonging to the trunk Aa and energizes such of the relays OLM1 - - OLM4 as are associated with idle secondary links. These relays connect ground to circuit 50, Figs. 7 and 8, to operate the relay ITM1 belonging to the final link that has been marked. Relay ITM1 energizes a relay SS which energizes the nearest relay ILM1, ILM5, &c. belonging to a horizontal row containing the marked tertiary link in the different tertiary switches, that is associated with an idle secondary link giving access to an idle primary link of the group A1. The energization of (say) relay ILM1, energizes the auxiliary coil TAS1 (particular to the marked tertiary link), the coil LAS1 in the corresponding row of the secondary switch in series with the coil ASa, and also the relay PR which energizes the " bar relays " ILC1, LBR1 of the horizontal rows in the secondary and tertiary switches corresponding to the chosen secondary link and the bar relay BR1 of the vertical row in the primary switch corresponding to the primary link. The bar relays BR1, LBR1 open contacts OC, SC, to busy the route. Release is dependent on the opening of circuit 60. The function of the bar relays LBR may be performed by the relays BR or the relays ILC. Connection with an idle line of a group. In case, in certain groups it is immaterial which of a number of outgoing links is used, some of the tertiary switches are omitted. One relay ITM is provided for a group of outgoing links and the relays ILC are replaced by resistances. This arrangement is fully described in a relay system in Specification 181,120. Specifications 181,119 and 187,580 also are referred to.