AT Commands Reference Manual - wireless netcontrol GmbH

Chapter 2: Introduction to AT Commands
AT Commands Structure
Command Structure
An AT command line may contain one or more commands. Delimiters are used to separate the
commands from each other, according to the following structure:
Prefix Command1 Delimiter Command2 Delimiter … CommandN Suffix
Each AT command has the "AT" prefix string.
Each AT command has the suffix .
The delimiter is either a semicolon ";" or none, meaning space (basic commands).
Each AT command has the following structure:
Token Mode Arguments
The following figure outlines the basic structure of an AT command line:
Command
line prefix
Extended commands are
delimited with semicolon
Command line
termination character
Subparameter
Read command for checking
current subparameter values
ATCMD1 CMD2=12; +CMD1; +CMD2=,,15; +CMD2?; +CMD2=?
Basic command
(no + prefix)
Subparameters
may be omitted
Extended command
(prefixed with +)
Test command for checking
possible subparameter values
Figure 2-2: Basic Structure of a Command Line
The following rules must be observed when issuing a command line to the modem:
• Every command line must begin with the letters AT.
• Several commands can be concatenated as one line, as long as the total line does not exceed
140 characters with semicolon characters.
• Characters:
Spaces are ignored. You can leave spaces between each command and between characters of a
command. You can also include punctuation in telephone numbers, and type commands in either
UPPERCASE or lowercase. For example, the following commands are identical:
ATDT8005551234 < Enter > or
atdt (800) 555-1234 < Enter >
Backspace character is allowed.
• To cancel a dialing command in progress, send any IRA character to the modem.
• To execute the command line, send the IRA character.
April 15, 2010 H24 - AT Commands Reference Manual 2-3