Specifications

ISU AT Command Reference Command Overview
Iridium Proprietary Version 2.45
20 June 2011 7
3 Command Overview
3.1 Command Types
The ISU employs two principle types of AT commands: basic and extended. The two types have differing
syntax used to query and adjust their settings. They also have unique reference standards.
A specific basic AT command is used to reference S-registers and query and adjust their settings. Its
syntax is similar to that of extended AT commands.
3.2 Basic Commands
Basic commands are industry standard and originally developed for Hayes-compatible PSTN modems. In
many cases, basic commands consist of a single ASCII alpha character.
In other cases, a special character precedes the alpha character. Prefix characters used in ISU basic
commands include &, \, %, and *.
Most alpha characters in basic commands are followed by a numeric parameter, n. To adjust its setting, a
basic command is entered with the appropriate numeric value of n. Note that if the numeric parameter n is
omitted from the basic command entry, a value of zero is assumed for n. For example, ATXn is set to a
value of 4 by entering ATX4, whereas it is set to value of 0 by entering either ATX0 or ATX.
To query a basic command setting, the AT&V command is entered to view the active configuration of a
group of basic commands.
Some basic commands listed in this document are marked with “No action, compatibility only”. In these
cases, the basic command is accepted in the same fashion as is with other modems, but has no effect on the
operation of the ISU, since it has no meaning in the Iridium
TM/SM
environment.
3.3 Extended Commands
Extended commands perform actions or set parameters that extend the capability of the ISU beyond that
which is allowed by basic commands. In some cases, they were designed for non-PSTN networks, such as
the GSM network.
Most extended commands include a prefix of + followed by a single alpha character. Prefixes used in ISU
extended commands include +C, +D, +G, +I, and +S. Extended commands designed specifically for the
Motorola Satellite Series product line include a -MS prefix.
Most extended commands include three alpha characters after the prefix, but some commands include just
one or two alpha characters after the prefix.
Some extended commands have a single execution mode. No further syntax is added after the prefix and
body of the command. For example, AT+GSN is entered as shown to query the ISU for its assigned serial
number (i.e. IMEI).
Some extended commands incorporate a test mode to query their range of valid responses. For example,
AT+CBC is entered as shown in execution mode to query the ISU for its battery connection and charge
status. The command is entered as AT+CBC=? in test mode to query its range of valid responses.
Some extended commands incorporate set, read, and test modes. For example, AT-MSVTR is entered as
AT-MSVTR=n in set mode to enable/disable receipt of DTMF messages. It is entered as AT-MSVTR? in
read mode to query its current setting and is entered as AT-MSVTR=? in test mode to query its range of
valid settings.
Extended commands are grouped as shown below.