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6.7
AT Commands
6.7.1
What are the AT commands?
They are model control commands that were developed by Hayes, a modem
manufacturer in the United States. At present, the AT commands are adopted in a
large number of modems for use with general telephone lines. The AT commands
are named as such because a character string, "AT" (meaning "attention") is
prefixed to each of them.
The AT commands that can be used by the MES include:
Basic commands (same as the commands that are generally used in most of
the modems)
Extended commands (commands added for Inmarsat)
The data corrections and data compression (MNP, V42, and V.42bis) as used
over telephone lines are not used on any satellite channel. Therefore, there is no
command available for them.
To enter a command, prefix "AT" to it like "ATA" and "ATE0" (except "A/"). Except
for some specific commands, you may want to describe multiple commands on a
single line, like "ATV1Q0." A different command may be placed immediately after
any basic command. However, a character ";" must be placed immediately after
any extended command.
Any command parameter enclosed in brackets ([ ]) may be omitted. If it is omitted,
the default value is assumed.
Note 1: Any parameter included in a command followed by (
the non-volatile memory.
Note 2: In principle, the commands that were specified in the SDM by Inmarsat
are employed, but some of the added and omitted commands or
parameters are different because of reasons related to the specification
of equipment.
6. 9.6k DATA COMMUNICATIONS
% ) may be stored in
6-13
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