Low voltage two wire to four wire telephone circuit converter apparatus

This abstract describes a low voltage two wire to four wire telephone circuit converter apparatus utilizing a series pair of amplifiers to provide a transmit data out signal that is referenced to analog ground. A pair of amplifiers is in parallel to receive data in single which is referenced to analog ground and apply it to the telephone unit. A signal adapter converts the telephone ring signal to a constant level for transmission over a digital channel in a fiber optic link.