Local Test; Circuit Test Mode - Oki ML420 Maintenance Manual

3.3

Local Test

3.3.1 Circuit test mode

3.3.1.1 Setting
(1) Diagnostic test (set by menu)
(2) Test connector
Connect the test connector shown in Figure C-9 to the interface connector
3.3.1.2 Function
After the settings outlined in Section 3.3.1.1 are completed and power is turned on, the serial
interface checks the message buffer memory and interface driver/receiver circuit. It then prints
characters.
To start and stop this test, push the SEL switch on the front of the printer.
Details of this test are explained on below.
(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.
42113901TH01 Rev.3
Equivalent to Cannon DB-25P
Figure C-9 Test Connector Connection Diagram
Oki Data CONFIDENTIAL
2
TD
RD 3
RTS 4
CTS 5
CD 8
SSD 11
20
DTR
DSR 6
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