Patent ID: 6538865
Filing Date: 2003-03-25
Classification: H04B,H04L

Abstract:
A fault-detecting device for a communication system using two-wire transmission lines for transmitting information signals opposite in phase to each other, comprising:first comparator means for comparing magnitudes between levels of information signals inputted through each of said two-wire transmission lines to obtain a resulting value as a main reception signal, second comparator means for comparing magnitudes between a level of an information signal inputted through one of said two-wire transmission lines and a first threshold value to obtain a resulting value as a first individual reception signal, third comparator means for comparing magnitudes between a level of an information signal inputted through the other one of said two-wire transmission lines and a second threshold value to obtain a resulting value as a second individual reception signal, first mismatch detecting means for determining a mismatch between said main reception signal and said first individual reception signal at a predetermined timing and generating a first mismatch detection signal when the mismatch has occurred, first frequency determining means responsive to the first mismatch detection signal for generating a first fault detection signal indicating a fault in the one of said two-wire transmission lines in accordance with a frequency of occurrence of said first mismatch detection signal, second mismatch detecting means for determining a mismatch between said main reception signal and said second individual reception signal at said predetermined timing and generating a second mismatch detection signal when the mismatch has occurred, and second frequency determining means responsive to the second mismatch detection signal for generating a second fault detection signal indicating a fault in the other one of said two-wire transmission lines in accordance with a frequency of occurrence of said second mismatch detection signal.