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AT Command Set Operation
Chapter 4:
AT Command Overview
The Dual V.34 modem supports the AT ( AT tention) command set, which includes the basic AT
command set and the extended commands sets: AT& , AT% , AT\ , AT: , and AT* . These
commands allow the user to obtain information from the modem, configure the modem, establish
data communications, test the modem and data communications system
In this chapter, a description of each command is provided in
which lists each command in alphabetical order along with its available options. Additional
information such as procedures and special considerations is provided for certain commands at the
end of this chapter in
AT Command Guidelines
Upon installation and/or powered up, the modem will be in the command mode and will be able to
accept AT commands from the terminal. The following guidelines should be understood by the
user when issuing AT commands to the modem:
•
Each command line must be preceded by the letters AT and followed by a carriage return
( Enter) . The only exception to this rule is the A/ command.
•
The A/ is used to repeat the last command entered. This is the only command that can be issued
without the AT prefix.
•
The modem acts on the command line only. The AT prefix, space, carriage return and line feed
characters are not considered as part of the command line.
•
When AT is entered, the modem detects the data rate and parity used by the terminal and
begins operating at that same data rate and parity until it gets changed.
•
Up to 40 AT command characters may be entered. Command lines that exceed 40 characters
will not be executed.
•
A carriage return character ( Enter ) must be entered at the end of the command line in order
for the modem to process the command(s).
•
Mistakes in the command line may be corrected by using the backspace key to move the cursor
over the character to be corrected. The AT prefix cannot be deleted in this manner.
•
After a command line is entered, the modem responds by sending a result code back to the
terminal. The terminal displays OK for a valid command return, and displays ERROR for
invalid return. Result codes will be ignored if the result code function is disabled or if the
communications software running on a computer emulating a terminal ignores result codes.
New commands cannot be issued until a response to the previous command is received. If there
is no response, a wait of three character times is required before the next command. If the DTE
rate is changed, then 1 second must elapse.
060R122-000
Issue 15
AT Command Details
.
SpectraComm Dual V.34 Modem
Installation and Operation
AT Command Reference Tables
4-1
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