3Com 56k User's Manual And Reference page 51

Any key Aborts off-hook dial/answer
operation and hangs up.
AT Required command prefix, except with A/,
+++, and A>. Use alone to test for OK
result code.
Bn U.S./ITU-T answer sequence
B0 ITU-T answer sequence
B1 U.S. answer tone
Dn Dials the specified phone number,
includes the following:
0-9 Numeric digits
#, * Extended touch-tone pad tones
L Dials the last dialled number
P Pulse (rotary) dial
R Originates call using answer
(reverse) frequencies
Sn Dials the phone number string
stored at position n (n = 0−3).
Phone numbers are stored with
the &Zn=s command
T Tone dial
Technical Reference
Dn (Continued)
, (Comma) Pause, see the
definition of the S8 register to
which it is linked
; (Semicolon) Return to
Command mode after dialling
! (Exclamation point) Flashes the
switch hook
/ (Back Slash) Delays for 125 ms.
before proceeding with dial
string
W Waits for second dial tone (X2
or X4); linked to S6 register
@ (At Symbol) Dials, waits for
quiet answer, and continues (X3
or higher)
$ (Dollar Sign) Displays a list of
Dial commands
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