PURPOSE: To provide the bus line testing system to easily discover the abnormality of a bus line, which is not normally used, with simple configuration.
CONSTITUTION: The above system is equipped with a bus line 100 connected to plural electronic units 1-n, bus master 200 to control the drive of the bus line 100 and the connection of the respective electronic units 1-n to the bus line 100 and return unit 300 to return the bus line 100 by beingenergized from the bus master 200. When the bus line 100 is not used, the above-mentioned bus master 200 tests the bus line 100 by energizing the return unit 300 and returning a test pattern signal at the return unit 300. Preferably, the return unit 300 is provided integrally with the last electronic unit (n) connected to the bus line 100.
YOGOSHI NORIYUKI
MIYAWAKI HIROTOMO
SUZUKI NORIYUKI
SHIRAI MASAHIRO
