28
C
HAPTER
5: U
SING
THE
M
ODEM
Attaching this information to faxes is known as
fax branding
. Refer to your fax
communication software documentation for details on how to comply with the
fax-branding requirement.
AT Commands
AT commands are set at the factory (factory settings are called
defaults
) to
perform specific modem functions in preselected ways. They can be used to
display call status or send and receive data with communications software such as
HyperTerminal.
Entering AT Commands
AT commands are instructions typed at the command line of any communications
application. A communications application is in command mode when the
application is started but the modem has not yet dialed. When your application is
in command mode, the AT commands you type are sent directly to the modem.
The most common way to enter AT commands is from terminal mode in your
communications software. The basic rules for entering AT commands are:
■
All AT command lines must begin with the prefix
AT
.
■
Spaces between command characters (and option characters) are ignored.
■
Command line parameters cannot exceed 255 characters.
■
Use a carriage return [Enter] to enter a command line. Commands take effect
as soon as they are received.
■
Type commands in either upper or lower case, not a combination.
■
If you leave the number off a command, zero is assumed. For example, if you
type
ATE
,
ATE0
is assumed.
A: Answer Mode
Causes the modem to attempt a handshake in answer mode.
D: Dial Number
Instructs the modem to go off-hook and execute the dial string which follows the
D. Commands which may be part of the dial string are listed below. Any
unrecognized character in the dial string is ignored. Once dialing is complete, the
modem attempts a handshake in originate mode (unless the R parameter is given).
.
0-9 Any number simply dials that number.
A, B, C, D, # or * (tone dial only) dials the indicated symbol.
P
Causes subsequent numbers to be pulse dialed.
T
Causes subsequent numbers to be tone dialed.
R
Forces the modem to dial a call in answer mode.
W
Causes the modem to wait for a dial tone using S7 as a time out.
