Parallel-connected telephone use determining circuit in a cordless telephone system and method thereof

摘要

A parallel-connected telephone use determining circuit using a microcomputer having therein an analog-to digital converter for determining an operation status of a parallel-connected telephone system connected to a telephone line. The circuit includes a rectifier for rectifying the variance of voltage applied through a telephone line, a voltage detector for detecting the variance of the voltage rectified from the rectifier, and a central processing unit (CPU) having an A/D converter incorporated therein for converting the voltage variance output from the voltage detector into a digital signal, for detecting the digital signal converted from the A/D converter and determining whether a parallel-connected telephone is in use.