Circuit for interfacing between an external signal and control apparatus

摘要

An input/output interface for a digital controller including an optical isolator coupling an input portion which formats an external signal to make it compatible with the optical isolator and an output portion comprising an RC network connected to a threshold detector with hysteresis to provide a filtered output logic signal in addition to an accompanying audio or visual signal. The interface, with slight modifications can be used with either DC or AC external signals.