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3.2.3 Call Control
3.2.3.1 D - Dial
This command directs the modem to go on-line, dial according to the entered string 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. In W-class models, the action of going
off-hook is affected by the status of the Line Current Sense input, if line current sensing
is enabled, and by the blacklist and delayed list. NOTE: If the ATD command is issued
before the S1 register has cleared, the modem will respond with the NO CARRIER result
code.
If +FCLASS=0 is selected, the modem will behave as a data modem and will attempt to
connect to another data modem.
The modem will have up to the period of time specified by register S6 or S7 to wait for
carrier and complete the handshake.
If this time expires before the modem can complete the handshake, the modem will go
on-hook with the NO CARRIER response. This command will be aborted upon receipt of
any DTE character before completion of the handshake.
If +FCLASS=1 or 1.0 is selected, the modem will behave as a facsimile modem and
attempt to connect to a facsimile machine (or modem) by entering the HDLC V.21
channel 2 receive state (as if +FRH=3 had been issued). This command will be aborted
upon receipt of any DTE character if the modem has not finished dialing. In this case,
the modem will go on-hook and return to command mode after displaying the NO
CARRIER message. If the modem finishes dialing, it will proceed as if the +FRH=3
command is issued. (Refer to the +FRH command to determine how the modem
behaves following this
stage.)
Syntax
D<modifier>
Defined Values
<modifier> The valid dial string parameters (modifiers) are described below. Punctuation
characters may be used for clarity, with parentheses, hyphen, and spaces ignored.
0-9 DTMF digits 0 to 9.
A-D DTMF digits A, B, C, and D. Some countries may prohibit sending of these digits
during dialing.
L Re-dial last number: the modem will re-dial the last valid telephone number. The L
must be
immediately after the D with all the following characters ignored).
P Select pulse dialing: pulse dial the numbers that follow until a "T" is encountered.
Affects current
and subsequent dialing. Some countries prevent changing dialing modes after the first
digit is
dialed.
T Select tone dialing: tone dial the numbers that follow until a "P" is encountered. Affects
current
and subsequent dialing. Some countries prevent changing dialing modes after the first
digit is
dialed.
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 (US) or S6 (W-class), the modem will
abort
the rest of the sequence, return on-hook, and generate an error message.
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