Diagnostic
4.1
4.
DIAGNOSTIC
Digicom ISDN modems have an automatic internal self test diagnostic that starts automatically
when the modem is turned on.
4.1.
DIAGNOSTIC ACTIVATION
When the SNM 70 is turned off and on, the internal self test diagnostic starts automatically to
detect any internal malfunction before the normal operation.
During the test, the TEST led present on the front panel is ON; if the diagnostic test is ok, after
4 sec. the led is turned off, otherwise the led flashes to indicate a malfunction.
On the SNM 70, the diagnostic tests can be activated using the AT commands using terminal
emulation on the PC.
4.2.
DIAGNOSTIC ACTIVATION
The SNM70 has a very powerfull command set to self-test the modem, the line, and the
remote equipment.
In this chapter you can find some simple procedures to implement the diagnostic features.
IMPORTANT
To activate the loop the modem must be set up without error correction (AT\N0).
4.2.1. LOCAL ANALOG LOOPBACK TEST (CCITT LOOP 3)
Scope of this test is to verify the modem itself. When the modem is Off Line type the command:
AT&T1.
This command forces the modem into local analog loop mode [simulating connection to itself].
You can send single characters, character strings, or files and they are received as sent from
your computer. To exit from test condition type the escape sequence (+++), and when the
response OK is displayed, enter the command AT&T0.
4.2.2. LOCAL DIGITAL LOOPBACK TEST (CCITT LOOP 2 LOCAL)
The objective of this test is to verify the COM port and the serial cable of your computer. When
the modem is Off Line type the command: AT&T3.
This command forces the modem in local digital loop mode [simulating the connection of send
data and receive data before modulation processor].
You can send single characters, character strings or files and they are received as sent from
your computer. To exit from test condition type the escape sequence (+++) and when the
response OK is displayed, enter the command AT&T0.
SNM7004.pm6
4/8/98, 14:46
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