17
U
SING
AT C
OMMANDS
AND
R
ESULT
C
ODES
This section discusses the following topics:
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When you use your telecommunications software to perform a task (such as dialing a phone
number), it uses the modem’s AT commands to perform the task. It is usually easier to let your
telecommunications software issue the commands for you than it is to issue the AT commands
yourself.
However, when your telecommunications software can not perform a task (or you don’t want it to),
you can issue the AT commands yourself. These commands can be used to perform various tasks,
from hanging up to changing your modem’s speaker volume.
Several chapters in this manual explain how to use the AT commands to accomplish specific tasks.
This chapter explains how the AT commands work. The commands are listed in AT Commands.
I
SSUING
AT C
OMMANDS
To issue AT commands, you must be in your software’s terminal mode — also called “local mode”
or “command mode.” In this mode, the commands you type go to the modem rather than to your
software or to the remote computer.
Some software uses terminal mode as soon as you start the program. To determine if you are in
terminal mode, type:
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