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3. AT COMMAND SYNTAX
For basic information on the AT command syntax, refer to section
V.25ter
and to GSM 07.07
section 4. This chapter describes the three different AT command formats and the default
value mechanisms for their parameters.
3.1 REGISTER
COMMANDS
Table 2. Register command format in command
description subsections
Command
Response
<n>
values
Set
Sn=<n>
x..y (default z)
Read
Sn? <n> xxx..yyy
The register command factory default value (&F) is given in parentheses under the column
‘<n> values’. The existence of a register command can be queried by giving a command
without equal signs or question marks (i.e. ATS3 returns OK, but it does not change the <n>
setting). <n> cannot be omitted when its value is set (i.e. ATS3= returns ERROR).
3.2 BASIC
COMMANDS
Table 3. Basic command format in command description subsections
Command
Description
Set/ Execute
CMD[x] for
value
x
CMDy for
value
y
The commands D (dial), A (answer) and O (return to online data state) also include columns
for possible result codes.
The basic command (no ‘+’ prefix) &F default value is underlined. If no value is underlined,
the setting of that command is not stored in the non-volatile memory (the command &Y is an
exception). If the command parameter is in brackets (usually zero), the parameter can be
omitted.
