Abstract: A relay matrix, especially a reed relay matrix for selectors in telephone exchanges, consists of a crossing point network, i.e. relays arranged in rows and columns constituting switching elements of speech paths, control unit and holding units common to such a network. The relays of the crossing point network are of the monostable reed-relay type. The through connection is of the two pole type i.e. each crossing point comprises just two make contacts. The wire connection between the matrices in the selector is limited to the speech wires since a continuous holding wire is not utilized. Addressing of the crossing points in a connection is carried out by means of a central processor by the setting up of a connection as well as by the releasing of the connection.

Abstract: In a relay matrix there are provided a plurality of control and holding circuits for selecting which of the relays are to be energized. The control and holding circuits which are associated with groups of relays include two-state devices which are triggered into a conductive state at the coincidence of a control signal and a minimum value control current and remain in that state after the termination of the control signal until the control current falls below the minimum value.