Extendable cross-bar switch for telephone exchange - uses electronic auto-commutator permitting connections between terminals and lines

摘要

A private electronic autocommutator using crossbar switching permits automatic connection of telephone conversations between extension telephones and between these telephones and external telephone lines. Extension of the autocommutator is by plug is printed circuit cards. A crossbar multiplexing electronic switch connects each subscriber line via the subscriber circuit to a user equipment. Lifting of the handset is signalled to permit dialling and connection of lines. Telephone network lines are connected to the switching system via a network circuit to permit signalling of state of external lines. An operator line is also connected into the system using controls.