A METHOD FOR PROTECTION OF COLLISION TRANSMISSION SIGNAL BETWEEN CARD KEY IN A PERSONAL IDENTIFICATION CARD SYSTEM

摘要

A method for preventing signal collision between card keys in a PIC system is provided to prevent failure in signal transmission caused by mutual propagation interference, in case of signal transmission of card keys which are registered in a vehicle PIC system. When card keys are registered, their respective unique delay times are differently set. If signals are received from a vehicle antenna(S100), each of the card keys waits for signal transmission during its own preset delay time(S110). Then, after signal transmission standby during each delay time, each of the card keys transmits an RF signal(S120-S140). Accordingly, collision between RF signals can be avoided as the card keys respectively transmit RF signals after waiting for signal transmission during individually set delay time.