5686G-PRO User Guide
Page
30
of
94
Copyright © 2018 USR, a Division of UNICOM Global
2.
Send
AT&T1
to the modem so it enters analog loopback mode. The CD status light will
illuminate.
3.
Type any recognizable data. It will be looped back by your modem's transmitter for
verification on your screen.
4.
When the test is completed, send +++ and then
AT&T0
to end the test.
Alternatively, you can end the test by sending
ATH
, or
ATZ
. Be careful, though,
because
ATZ
resets the modem in addition to ending the test.
In either case, the modem responds with OK. If the modem sends an ERROR message, you
have issued an invalid command.
5.
Send
AT&M4
, unless you used a reset command (
ATZ
).
Note:
If the Courier Lite 56K Business Modem is in online command mode, still connected to a
remote modem, and you send AT&T1 or AT&T8, it drops the call, enters analog loopback mode, sends
a CONNECT result, and waits for loopback characters.
Stopping a Test (AT&T0, ATS18)
To stop a test, send
AT&T0
to the modem, or set Register S18 to a specified number of seconds (for
example,
ATS18=10
). When the 10 seconds are up, the modem will stop the test automatically and
return to Command Mode. Send
ATH
to the modem to hang up, or send
ATZ
to hang up and reset the
modem to its defaults.
Note:
If you use the S18 test timer, but in the process of testing you issue an ATZ command, S18
resets to zero and the timer is disabled. You cannot store a value for S18 in NVRAM; its power-on and
reset default is always zero.
Using AT&T8
This analog loopback option causes the Courier Lite 56K Business Modem to send an internal test
pattern to its transmitter and loop it back to the receiver. An internal error detector counts any
errors and, when the test is ended, sends the number of errors or 000 (no errors) to the screen.
Since you don't type anything during this test and the Courier Lite 56K Business Modem does not
send anything to the screen, this option verifies only the Courier Lite 56K Business Modem. If there
are no errors but your problem continues, it may be at the computer interface.
1.
Send
AT&M0&N3S14.0=0
to the modem to prepare for testing.
This command disables error control, fixes the connection rate at 2400 bps, and makes the
Courier Lite 56K Business Modem return to command mode when you type +++.
