Communications unit for voice and data

Abstract

A communications unit that allows alternate voice and digital data transmissions over a single telephone line. A communications unit, at each of two locations that connect through telephones, includes a trunk signal path that connects to a telephone line and a telephone signal path that connects to the telephone. A digital data signal path connects to digital data processing equipment, usually in the form of an input/output unit in a digital data processing system. A monostable switch interconnects the telephone line and trunk signal paths in a stable conduction to enable voice communications. When the digital data signal path is used, a control automatically shifts the monostable switching means to its astable state thereby to isolate the telephone signal path and to interconnect the trunk signal path and the digital data signal path to allow data communications. When the data communications end, the control automatically allows the switching means to return to its stable state thereby to again enable voice communications. A testing and monitoring unit connects to the telephone signal path, the digital data signal path, and the control means to enable selective testing and monitoring of the communications unit.

Dependencies are inferred from the claim text.