DATA REPEATER AND INTERPHONE SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a data repeater that can increase the number of connected communication terminals without changing the characteristic impedance of a transmission line or extend the length of the transmission line and correctly transmit communication data or a synchronizing signal. SOLUTION: The data repeater 100 is provided with a data reception section 52 that receives a system synchronizing signal transmitted to a uplink transmission line 110, a system synchronizing signal detection section 53 that detects the system synchronizing signal, a system synchronization PLL 54 that generates a clock synchronously with the system synchronizing signal based on the detection timing of the synchronizing signal and a phase of data, and a system synchronizing signal generating section 56 that generates the system synchronizing signal based on the clock signal generated by the system synchronization PLL 54. The data repeater 100 modulates the system synchronizing signal generated by the system synchronizing signal generating section 56 and outputs the modulated system synchronizing signal to a downlink transmission line 120.