Identifier for manual switchboards with conference facility

Abstract

A line identifier at a telecommunication switchboard comprises a matrix of magnetic-induction elements serving as current sensors for detecting a request for establishing a connection between a selected incoming line and a selected outgoing line. The sensors are connected to a multiplexer for providing samples in a time-division mode to a logic circuit controlled by a pair of microprogrammers and addressing a read/write memory for storing information on the states of the sensors. The logic network, upon receiving from a sensor an identification request for a selected outgoing line, such request implicitly coding a selected input line, activates a relay which closes a circuit enabling the energization of a sensor whose output signal to the logic network identifies the outgoing line selected via the switchboard for connection to the prior-identified incoming line. Upon successful identification of a selected incoming line and at least one selected outgoing line, the logic network emits energization signals to a pair of relays which thereupon break the circuits energizing the sensors and establish a link between the selected incoming line and the selected outgoing line. The logic network is connected via its control microprocessors to a computer for communicating thereto the identities of interconnected lines. The logic network with its associated multiplexer and microprocessors may be duplicated for cross-checking operations.