Patent ID: 6389061
Filing Date: 2002-05-14
Classification: H04L,H04M

Abstract:
A bidirectional telephone line isolation system for providing an isolated communication channel for digital signals in a forward direction and in a reverse direction across a capacitive telephone line isolation barrier, the system comprising:a powered system on a first side of the capacitive telephone line isolation barrier, the powered system comprising, a powered side encoder circuit having an input terminal for receiving forward direction digital signals to be transmitted in the forward direction across at least one capacitor of the capacitive telephone line isolation barrier, and a powered decoder circuit having an input to receive reverse direction digital signals transmitted in the reverse direction across at least one capacitor of the capacitive telephone isolation barrier, the powered decoder circuit decoding signals transmitted in the reverse direction across the capacitive telephone line isolation barrier; and an isolated system on a second side of the capacitive telephone line isolation barrier, the isolated system comprising, a clock circuit having an input coupled to at least one capacitor of the capacitive telephone line isolation and an output providing an isolated clock signal to circuitry in the isolated system, an isolated decoder circuit having an input to receive forward direction digital signals transmitted in the forward direction across at least one capacitor of the capacitive telephone isolation barrier, the isolated decoder circuit decoding signals transmitted in the forward direction across the capacitive telephone line isolation barrier, an isolated encoder circuit having an input for receiving digital signals to be transmitted in the reverse direction across at least one capacitor of the capacitive telephone isolation barrier, and an isolated power supply circuit coupled to at least one of the isolation capacitors, the power supply circuit generating a DC power supply from at least one signal received across the capacitive isolation barrier.