Patent ID: 7249293

Claim:
A method for detecting a device which causes a bit reversal when the device is in trouble, comprising: demultiplexing a first serial signal into D(1)-D(N) signals, inputting the D(1)-D(N) signals into devices E( 1 )-E(N−1) and a channel marking device E(N) respectively, outputting D′(1)-D′(N−1) signals from the devices E( 1 )-E(N−1) and a D′(N) signal from the channel marking device E(N), wherein the channel marking device E(N) outputs the D′(N) signal by changing the D(N) signal by a certain changing method, multiplexing the D′(1)-D′(N) signals into a second serial signal, finding the D′(N) signal in the second serial signal which has a bit reversal, detecting a device E(X) which causes the bit reversal based on bit positions of a D′(X) signal and the D′(N) signal, wherein an order of bits between the first and the second serial signals is maintained.