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MultiModemISI Hybrid Series, ISIHI-2S 67
Chapter 4—MODEM AT Commands, S-Registers, Result Codes
Modem
Dialing Commands
Use dialing commands to dial and hang up.
D
s
Dial
s
= phone number
Default: none
The letter
D
in a command causes the modem to dial the telephone number immediately
following it. For example, if you type ATD5551212<cr>, the modem dials the number
555-1212.
The ISIHI-2S modem supports several dialing methods. With the D command, you can
specify either pulse (ATDP) or tone (ATDT) dialing. You also can modify the dialing
command with several other characters that are explained in the
Dial Modifier
Commands
section, later in this chapter.
The modem also lets you select either smart (wait-for-dial-tone) dialing or blind dialing.
With smart dialing, the modem waits for and detects dial tones and busy signals. With
blind dialing, the modem works with timed pauses (determined by the value of register
S6), not dial tone and busy signal detection. See the X command for more information on
blind and smart dialing.
H
n
On-Hook/Off-Hook
n
= 0 or 1
Default: 0
Use the H command to make the modem hang up (go on-hook) or simulate the action of
picking up a telephone handset (go off-hook).
H0 (or H) hangs up the modem
H1 brings the line off-hook, just as if you had picked up the telephone handset.
It is not necessary to use the H1 command to bring the line off-hook when using the D
command. The modem automatically goes off-hook when you press E
NTER at the end of
the dial command.
Dial Modifier Commands
The dial string can include the digits
0
through
9
, the pound sign (
#
), the asterisk (
*
), and
the letters
A
,
B
,
C
, or
D
. The latter are used by some PBXs; the exact function will
depend on the PBX manufacturer’s feature set and implementation. There are also
several command characters, called “dial modifiers,” that can be included within a dialing
command after the letter
D
. Their functions include pulse or tone dialing, pauses in the
dial sequence, automatic redials if a number is busy, and reverting to command mode or
switching to answer mode after dialing.
L Redial Last Number
Default: none
You can redial the last number dialed by entering L immediately following the dial
command (ATD). This command is handy if you encounter a busy signal and want to try
the call again.