Pentomat T private automatic branch exchange

A medium size private exchange is described which is based on a Pentaconta crossbar switch with 14 horizontal bars (one used for the change-over), providing 52 outlets. Subscriber sets are of pushbutton type operating on DC. "Line lockout" is provided which releases the exchange circuits if the call is not proceeding as it should, so as to prevent undue loading of the exchange equipment. Electronic components and reed relays are used in all code-handling circuits; varistors are employed for spark quenching on some contacts; connections are of the wrapped type. Traffic capacity is up to 10 erlangs/50 lines. The traffic flow and many special facilities are explained, but no detailed circuits are provided.