5
AT? - Read Selected S-Register
This command reads and displays the selected S-Register.
A - Answer
The modem will go off-hook and attempt to answer an incoming call if correct conditions are met.
Bn - CCITT or Bell
When the modem is configured to allow either option, the modem will select Bell or CCITT modulation for a
line speed connection of 300 or 1200 bps according to the parameter supplied. Any other line speed will use
a CCITT modulation standard.
B0
Selects CCITT operation at 300 or 1200 bps.
B1
Selects BELL operation at 300 or 1200 bps. (Default)
Cn - Carrier Control
This command is included for compatibility only, and has no effect other than returning a result code. The only
valid parameter is 1.
Dn - Dial
This command directs the modem to go on-line, dial according to the string entered and attempt to establish
a connection. If no dial string is supplied, the modem will go on-line and attempt the handshake in originate
mode.
NOTE:
If the ATD command is issued before the S1 register has cleared, the modem will respond
with the NO CARRIER result code.
Dial Modifiers. The valid dial string parameters are described below. Punctuation characters may be used
for clarity, with parentheses, hyphen, and spaces being ignored.
0-9
DTMF digits 0 to 9.
*
The "Star" digit (tone dialing only).
#
The "gate" digit (tone dialing only).
A-D
DTMF digits A,B,C, and D.
J
Perform MNP10 link negotiation at 1200 bps.
K
Enable power level adjustment during MNP10 link negotiation.
L
Re-dial last number.
P
Select pulse dialing.
T
Select tone dialing.
R
Ignored.
S=n
Dial the number stored in the directory.
!
Flash: the modem will go on-hook for a time defined by the value of S29.
W
Wait for dial tone: the modem will wait for dial tone before dialing the digits following "W". If
dial tone is not detected within the time specified by S7, the modem will abort the rest of the
sequence.
@
Wait for silence: the modem will wait for at least 5 seconds of silence in the call process
frequency band before continuing with the next dial string parameter. If the modem does not
detect these 5 seconds of silence before the expiration of the call abort timer (S7), the modem
will terminate the call attempt with a NO ANSWER message. If busy detection is enabled, the
modem may terminate the call with the BUSY result code. If answer tone arrives during