The parameters set by the various AT commands in this appendix are applied to all
subsequent calls and will be used each time you place a call. As such, your custom
settings will be available until you power down the modem. These settings are lost upon
power-down. New revisions of the modem’s firmware implements the ability to store
these commands even through a power-cycle. Please note any attached information
relating to these firmware revisions.
The modem also gives you automatic support of all AT commands that are unknown to
the modem but are supported by your cellular carrier. Since the carrier may charge you
for the air time used for this connection, the modem's autoconnect ability is disabled by
default. Issue the:
AT+CXT=1
†
command to enable this mode.
12.2 Command Line Syntax
A command line consists of the attention code followed by one or more commands and
terminated by an end of line code. The attention code is the character pair "
AT
" or "
at
".
By default, the end of line character is the ASCII CR character (decimal 13), unless it is
changed by the S3 command. The ASCII CR character is equivalent to one keystroke of
the ENTER key. Refer to the "S-Registers" section 12.5 for more information on this
command. Spaces are ignored (unless within quotes) and may be inserted between
arguments within the AT command line to make it more legible, if desired.
The Basic and S-Register commands may follow each other on the command line without
any separating delimiters. The Extended Format Commands (those beginning with a "+"
character) must be terminated with a semicolon ";" if they are followed by another
command on the same line. The ";" character is not required after the last command on
the line.
Commands may be edited using the backspace key, but backspace will not delete the AT
attention command at the beginning of the command line.
The
A/
†
command repeats the last command line received by the modem. The
A/
is not
followed by a carriage return.
12.3 Result Codes
After issuing a command, a result code will typically be displayed on the screen to inform
you if the command was successful, unsuccessful, improperly formatted, etc. When in the
command mode, eight possible result codes may be returned. The result codes can be set
to display as either digits or words by accessing the Verbose command. The digit code is
returned when the Verbose mode is OFF (
ATV0
); the word code is returned when
Verbose is ON (
ATV1
). See the
"Basic AT Parameters Table"
, section 12.4 for more
information on Verbose. Extended result codes may also be returned. The result codes are
listed in the following table.
Result Codes Table
Digit Verbose
Description
0
OK
Command executed without errors.
1
CONNECT
Connected to remote modem.
2
RING
Incoming Call.
3
NO CARRIER Carrier from remote modem lost or never present.
4
ERROR
Error in the command line.
6
NO DIAL TONE No dial tone detected within time out period.
