Patent ID: 6192125
Filing Date: 2001-02-20
Classification: H04M

Abstract:
A telephone line interface for interfacing between a telephone line and a device, said interface comprising:an input connectable to said telephone line;an output connectable to said device;a circuit having first and second connections connected across said input for terminating the telephone line voltage and current;first and second optocouplers each connected across said circuit; said first optocoupler having one side of its input connected to said first connection of said circuit to control the impedance presented by said line circuit to said telephone line via said connected input and the other side of its input connected to said second connection of said circuit, said second optocoupler having one side of its output connected to said first connection of said circuit and the other side of its output connected to said second connection of said circuit;wherein an output of said first optocoupler is connected to a receive portion of said output and wherein the input of said second optocoupler is connected to a transmit portion of said output.