Using At Commands; At Command Guidelines - AT&T DataPort PCX Modem User Manual

Using AT Commands

You can change the way your modem works by using AT
commands. However, your modem's factory default
configuration works for most applications; also software in your
PC may automatically reconfigure your modem as required. You
should find that you rarely need to enter AT commands yourself.
If you do, however, please read AT Command Guidelines first.

AT Command Guidelines

The following are guidelines for using AT commands.
G
Most AT commands are entered using the format AT Xn
where X is the AT command and n is the specific value
for that command. Some of the modem's internal
settings, called S-registers, are changed directly using a
command of the format ATS r = n , where r is the
S-register number and n is the value it is to be set to.
G
AT commands must be entered while the DataPort PCX
modem is in Command mode. When the DataPort PCX
modem is in online Command mode (when the modem
is online with another modem) and RPI is enabled, the
only valid AT command is ATH. Command mode is an
idle state in which the modem interprets entries from the
computer as commands, not data.
G
The escape sequence (which consists of three
consecutive plus characters — +++) is used to enter
online Command mode from Data mode. Data mode is a
state where all entries made from the computer are
considered data and are transmitted and received
between modems. To return to Data mode from online
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Issue 2 July 1995
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