Oki PACEMARK 4410 Service Manual page 211

(1) The program revision using two numerical characters is printed.
(2) "LOOP TEST" is printed.
(3) Memory is checked for the message buffer.
(4) Prints "OK" is printed if the memory check is OK and "BAD" is printed if the memory check
fails.
(5) Output level to DTR, RTS, and SSD signals is dropped low. If DSR, CTS, or CD signals is
High, "IF BAD" is printed. If DSR, CTS, and CD signals are all Low, "IF OK" is printed.
(6) Output level to DTR, RTS, and SSD signals is raised high. If DSR, CTS, or CD signals is Low,
"IF BAD" is printed. If DSR, CTS, and CD signals are all High, "IF OK" is printed.
(7) Transmits characters codes from 20H to 7FH is transmitted by SD signal. At the same time,
characters are received by the RD signal and stored in the message buffer.
(8) The characters that were stored in the message buffer as indicated in (7) are printed.
(9) Steps (1) through (8) are repeated until test is interrrupted.
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