Chapter 4: Troubleshooting 27
that the COM port resources used by the mo-
dem are not being used by any other device,
such as a soundcard.
Problem: You type an AT command line in a terminal
application and press Enter, but your mo-
dem fails to execute the command line. Or
there was no response after executing a
command.
Solution: Be sure you type AT at the beginning of the
command line.
Make sure the communications software is
configured for the same COM port as your mo-
dem.
Be sure your modem is not in data mode when
you type the command. Use the escape char-
acter sequence to switch to terminal mode
(The default escape sequence is to wait at least
one second, type +++, and wait another second
or more.)
If you typed a command but did not receive an
OK response from your modem, the E0 and Q1
commands may be in effect, disabling echo
and responses. Verify this with the &V com-
mand. To enable echo and responses, type
ATE1Q0 and press Enter.
Problem: The modem speaker volume is too low or
too high.
Solution: If the software allows you to control the vol-
ume, make sure the speaker is enabled and
set to a comfortable volume.
If the software does not have speaker settings,
add one of the AT commands listed below to
the initialization string:
L1 for low volume
L2 for medium volume
L3 for highest volume
M0 to turn the speaker off entirely
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