- All of the functions of the 3157 main unit, except for powering on and off, can be controlled via the RS-232C interface. However, the ":START" command works in a state in which the momentary OUT settings are disabled even though the momentary OUT settings have been set.
- The beeper sound can be turned on and off.
- The unit can be reset.
- Test results can be printed on the optional 9442 PRINTER.
- Connecting with the optional 3155 LEAK CURRENT HiTESTER enables testing and the test results can be saved and printed together with the 3155 leakage current test results.