The XE0016 integrates a two-to-four wire convertor, Caller ID circuit, ring detection, loop current holding circuit, solid-state hookswitch and telephone line transformer into a compact single-in-line module. The Caller ID circuit allows the Caller ID signal to pass through the XE0016. It also permits monitoring of other signals on the line without seizing the line. The integral two-to-four wire convertor separates the transmit and receive signals and is essential for full duplex communications.