Patent ID: 7216269

Claim:
A signal transmit-receive device that performs mutual conversion of parallelism factor of signals between communication devices to perform transmission and reception, the transmit-receive device comprising: a first signal converter converting signals, inputted from a first communication device and having a parallelism factor of n (n≧1), into signals having a parallelism factor of m (m≧1); a data transmitting circuit transmitting the converted signals to a second communication device; a data receiving circuit receiving signals transmitted from said second communication device and having a parallelism factor of m; a second signal converter converting signals received in said receiving circuit into signals having a parallelism factor of n to provide the converted signals to said first communication device; an error detecting circuit determining, when a first test signal is inputted to said first signal converter, whether an error exists in outputs of said first signal converter or not; a loopback means for transmitting an error detection result of said error detection means to data receiving side at a data transfer rate lower than that of said data transmitting circuit; and a test signal generation circuit generating a second test signal reflecting the transmitted error detection result and inputting the second test signal into said second signal converter to converting the parallelism factor of the second test signal and to provide said first communication device with the converted second test signal as a loopback test result.