Specifications

Chapter 1 – Introduction
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371B) 10
1.4 AT Command Syntax
The “AT” or “at” prefix must be set at the beginning of each command line. To terminate a command line enter <CR>.
Commands are usually followed by a response that includes “<CR><LF><response><CR><LF>”. Throughout this
document, only the responses are presented, <CR><LF> are omitted intentionally.
Table 1.4: Types of AT commands and responses.
AT Cmmand Type Syntax Function
Test command AT+CXXX=? The mobile equipment returns the list of parameters and value ranges
set with the corresponding Write command or by internal processes.
Read command AT+CXXX? This command returns the currently set value of the parameter(s).
Write command AT+CXXX=<...> This command sets user-definable parameter values.
Exec(ution)
command
AT+CXXX The execution command reads non-variable parameters determined by
internal processes in the GSM engine.
1.4.1 Using Parameters
• Optional parameters are enclosed in square brackets. If optional parameters are omitted, the current
settings are used until you change them.
• Optional parameters or subparameters can be omitted unless they are followed by other parameters. If you
want to omit a parameter in the middle of a string it must be replaced by a comma. See also example 1.
• A parameter value enclosed in square brackets represents the value that will be used if an optional
parameter is omitted. See also example 2.
• When the parameter is a character string; e.g., <text> or <number>, the string must be enclosed in quotation
marks (e.g., “Charlie Brown” or “+49030xxxx”). Symbols in quotation marks will be recognized as strings.
• All spaces will be ignored when using strings without quotaton marks.
• It is possible to omit the leading zeros of strings which represent numbers.
• If an optional parameter of a V.250 command is omitted, its value is assumed to be 0.
Example 1: Omitting parameters in the middle of a string
AT+CCUG? Query current setting
+CCUG: 1,10,1
OK
AT+CCUG=,9 Set only the middle parameter
OK
AT+CCUG? Query new setting
+CCUG: 1,9,1
OK
Example 2: Using default parameter values for optional parameters
AT+CFUN=7,0 Activate CYCLIC SLEEP mode, don’t reset ME
OK
AT+CFUN? Query ME mode
+CFUN: 7
OK
AT+CFUN= Set ME back to normal (default parameters: 1,0)
OK
+CFUN: 1
OK
1.4.2 Combining AT Commands on the Same Command Line
You may enter several commands on the same line. This eliminates the typing of “AT” or “at” before each
command. Instead, it is needed only once - at the beginning of the command line. Use a semicolon as
command delimiter.
The table below lists the AT commands you cannot enter together with other commands on the same line.
Otherwise, the responses may not be in the expected order.
AT Command Type Comment
V.250 commands with FAX commands (Prefix AT+F)
GSM 7.07 commands with AT commands, Prefix AT^S)
GSM 7.05 commands (SMS) To be used as standalone commands
Commands starting with AT& To be used as standalone commands
AT+IPR To be used as standalone commands
Note: When concatenating AT commands please keep in mind that the sequence of processing may be different
from the sequential order of command input. Therefore, if the consecutive order of the issued commands and
associated responses is your concern, avoid concatenating commands on the same line.