PRIVATE BRANCH EXCHANGE, TELEPHONE SET, AND TELEPHONE SYSTEM WITH THEM

摘要

PROBLEM TO BE SOLVED: To construct a network for data communication without requiring new wiring by utilizing a telephone extension line laid on a premise in a telephone system. SOLUTION: The PBX (Private Branch Exchange) 2 transmits a superimposed signal of a transmission data signal modulated and converted into an analog signal and a transmission voice signal to telephone sets 3, 4, 5 via extension lines 13, 14, 15. Furthermore, the PBX 2 receives a superimposed signal of a reception data signal and a reception voice signal from the telephone sets 3, 4, 5 via the extension lines 13, 14, 15, extracts the reception data signal and the reception voice signal, respectively, converts into a digital signal and demodulates the reception data signal. Each of the telephone sets 3, 4, 5 also includes the similar function and communicates with the PBX 2 via the extension lines 13, 14, 15. COPYRIGHT: (C)2009,JPO&INPIT