Communications interface providing isolation and ringdown features

摘要

A communications interface having an isolation circuit for signals from a plain old telephone set (POTS) device to communications electronics. The communications interface having an isolated power supply. The isolated power supply including a flyback transformer for a current loop supply and an isolated power source The telephone line isolation circuit having an optically isolated off-hook detection circuit and an isolation transformer for isolating communication electronics from the telephone current loop. The telephone line isolation circuit providing a ringing circuit for ringing a current loop device, such as a standard plain old telephone system (POTS) device.