IE40820L - Telecommunications exchange - Google Patents

Abstract

1501291 Automatic exchange systems COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS CIT-ALCATEL 28 Feb 1975 [7 March 1974] 08408/75 Heading H4K A telecommunications exchange includes switching network, a network control unit connected to input junctors, output junctors and registers over common signalling busses and signalling between the junctors or junctors and registers is effected over a said common signalling busses and via a said control unit. As described the invention is applied to a four-wire cross-bar transit exchange. The network is symmetrical about the centre stage GS and each connection is set up in duplicate using both halves of each matrix crosspoint through which a connection passes. Each ten contact crosspoint is split into two groups of five contacts four of which are used for each speech path, the fifth contacts being connected to vertical control wires connected to interrogation elements L3 used in the path search, a path being selected by a control circuit CC. For an outgoing call a free register AN is selected and connected to a calling line by a finder CH and when sufficient digits have been dialled a "test unit" L4 enables a unit NA requesting connection to a path selection circuit CC. Unit NA connects test unit L4 and other calling test units L1, L2 and L3 which indicate the state of break contacts in each of the switching line verticals, to the path selection circuit. The network is controlled by two processors G 1 and G2 each of which stores words specifying for each call, the calling and called junctors and the register employed. The processor seized for routing a call is freed immediately after setting up a call and is seized again when required for the exchange of line signals by the junctor on the side from which the signal comes. Each junctor and register circuit includes a relay assembly (Fig. 3, not shown) including a relay for each other circuit to which that circuit has access, a transmit relay and a receive relay. A circuit wishing to send signals connects a diode across a pair of terminals thus interconnecting a row conductor and a column conductor in an identification matrix (Fig. 4, not shown) in the associated processor. The processor emits the coded address of the calling circuit to a calling unit address decoder which marks the calling circuit transmitting potentials back to the processor via contacts characteristic of the identity of the circuit to which access is required. The latter is identified by the processor and similarly addressed. [GB1501291A]