A High Voltage Line Interface Circuit for PBX Applications
01 January 1988
This paper describes a high voltage Line Interface circuit for PBX applications which includes (1) Five 300V switches for opening the channel, ringing access and message waiting; (2) Ringing State supervision circuitry; and (3) A digital interface to a controller IC. Additional circuitry for zero crossing switching and to insure break before make switch operation is also included.