TELEPHONE SYSTEM, CORDLESS TELEPHONE SYSTEM, AND UPPER-LEVEL DEVICE

摘要

PROBLEM TO BE SOLVED: To enable units in a cordless telephone system accommodated by an upper-level device to accurately synchronize with each other without connecting the upper-level device and the TDMA/TDD cordless telephone system with wires.SOLUTION: A master unit and a slave unit in a cordless telephone system accommodated by an upper-level device perform TDMA/TDD radio communication with each other. The master unit can receive a transmission signal which another master unit transmits to a slave unit paired with the other master unit and can transmit a transmission signal to the slave unit paired with itself through a radio communication circuit. A PLL unit 4423 uses the transmission signal from the other master unit received through the radio communication circuit as a reference signal, and aligns the phase of the transmission signal from itself with the reference signal. A control unit controls the PLL unit 4423 to use a transmission signal from a prescribed master unit among transmission signals received through the radio communication circuit as a reference signal.SELECTED DRAWING: Figure 1