PRIVATE BRANCH EXCHANGE, TELEPHONE TERMINAL, AND TELEPHONE SYSTEM HAVING THE PRIVATE BRANCH EXCHANGE AND THE TELEPHONE TERMINAL

摘要

A PBX transmits a superimposed signal to telephones via internal lines, the signal being generated from a transmission data signal modulated and converted into an analog form and a transmission voice signal. The PBX also receives a superimposed signal from the telephones via the internal lines, the signal being generated from a reception data signal and a reception voice signal. The PBX then retrieves the reception data signal and the reception voice signal separately, and digitally converts and modulates the reception data signal. The telephones also have similar functions as those of the PBX and communicate with the PBX via the internal lines.