Capacitively coupled ring detector with power provided across isolation barrier

摘要

A communication system is provided with a capacitive isolation barrier in which at least a portion of the ring detection circuits may be integrated into the line side circuitry. Moreover the ring detection circuits on the phone line side of the isolation barrier may be powered at least in part by power transmitted from the powered side of the isolation barrier to the phone line side of the isolation barrier through the barrier capacitors. A capacitive interface may directly connect the ringer circuitry on the phone line side of the barrier to the TIP/RING lines. The capacitive interface operates to linearly attenuate the TIP/RING signal voltage levels from the high phone line levels to levels within integrated circuit technology limitations.