Oki Microline Ml184T+ Handbook page 85

Performing the Circuit Test
A circuit test checks the serial inerf ace to ensure that the proper signals
are being sent on the active lines. The test provides a printout notice indicating
whether the test was performed successfully. After you remove the printer
cabinet, proceed as follows:
1. Set switch #6 to OFF, selecting the circuit test.
2. Disconnect your interface cable and connect the test cable.
3. Turn the printer on, leaving the cabinet off; the test should produce
the following results:
LOOP TEST is printed
RAM 2K is printed
The message buffer is checked. If memory is normal, OK is printed. If
memory is faulty, BAD is printed. Signals DTR, RTS, and SSD are set to
low (–). If CTS, DSR, or CD is positive, "IF BAD" is printed.
4. If you received a BAD message, something is wrong with your serial
interface. If you are unable to diagnose the problem contact your nearest
OKI dealer for further assistance.
5. Reset switch #6 to the ON position.
6. Replace the printer cabinet or proceed to the following instructions on
the monitor mode test.
Appendix B: Interface Cable B -- 11