GE 68K System User Manual

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CPM

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D20
D20 Base

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D20 ME
D20 Base

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D20/200
CCU Base

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D20/200 ME
CCU Base

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D25

Use this command to start one of these two serial port test procedures:
•  an automatic loop-back test of the defined serial port

−  transmits and receives a series of characters of different formats.

•  manually forcing the mark or space line states from the RS-232 drivers

−  allows you to monitor and adjust modem levels or frequencies.

Below is usage and syntax information for this command

CPM / D20:                           st /(f | l) port

CCU / CCUME / D25:          st /(f | l) port [baud]

/f

= force mark or space states

/l

= automatic loop-back test

port

= serial port to test (COM#)

baud

= data rate in bps (decimal)

Type st /l com7 9600 and press 

ENTER

.

Results: This forces the RS-232 transmitter driver for

communications port seven (7) to perform the loop-
back test at 9600 bps.

The system displays the current state of the test.
Cancel the force test manually with 

CTRL

-

C

.

The loop-back test terminates either on an error or on
completion of the test.  The monitor displays the
prompt after stopping either test.

•  These tests temporarily assume control of the specified

communications port, and disrupt any current activity.

•  They may also, depending on the application, affect

subsequent operation.

To ensure that you avoid this, you must reboot the system
when you complete all testing.