Apple Express Fax/Modem - Manual (Page 130)

Standard AT commands
AT The attention command prefix The prefix AT must precede every
command. The remainder of the command line contains commands for
the modem. The command line must end with a carriage return. If AT is
sent alone (that is, it is followed by a ), then no command is
executed but an OK result code is returned.
A Answer The A command forces the modem to go off-hook in answer
mode. The modem then starts sending the answer tone (CCITT answer
tone independent from the B setting) unless the modem is set for leased
line (&L command) state. If no carrier signal is received from the
telephone line within the number of seconds specified by register S7,
the modem goes on-hook.
This command must be the last on a command line. Sending any
character to the modem during call establishment will abort the
command and generate a NO CARRIER result code.
Bn Communication protocol category preference This command
determines which communication standard will be used for the next
connection.
0 CCITT mode
1 Bell 103 and Bell 212A, instead of V.21 and V.22, in case of
fallback
D Dial This command signals the modem that the numbers, letters,
and commas that follow are all part of thetelephone number it
should dial.
You may include other dial command characters in combination with
the D command: T, P, comma (,), W, colon (:),“at” sign (@),
exclamation point (!), R, semicolon (;), and S=
n. Each of these
optional modifiers is described in the following sections. For clarity
sake, you may also use other characters or symbols (for example,
parentheses, hyphens, and spaces) without affecting the number.
In addition to the digits 0 through 9, your modem can also dial the six
special characters (*, #, A, B, C, D) found on some Touch-Tone dial
telephones.
118 A P P E N D I X B