Multi-Tech Systems MT3334HD8 User Manual

Page 31

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3 AT Commands

CommPlete Communications Server

25

%DCn AT Command Control

n

= 0 or 1

Default: %DC0

The %DC command allows you to disable the modem’s ability to respond to AT commands. It can be used
with auto answer applications in which no call origination is required, with some UNIX applications, and
with other applications that require you to disable the modem’s command mode.

%DC0

enables command mode.

%DC1

disables command mode.

Note:

If you save %DC1 as part of your default configuration, you can re-enable command mode by typing

AT%DC0

and pressing E

NTER

in the first ten seconds after you power up the modem.

&CDn Cleardown at Disconnect

n

= 0 or 1

Default: &CD0

In the V.32, V.32bis, and V.34 protocols, a cleardown is sent by one of the modems to signal the other
modem that it is going to hang up. A cleardown is rate renegotiation in which the modem that is hanging
up tells the other modem that it has no speeds that it can connect at. It is designed to help the remote
modem detect a hang-up. However, it does take a second or two to send the cleardown. If you find this
delay unacceptable, you can disable cleardown by using the &CD command.

&CD0

enables cleardown at disconnect.

&CD1

disables cleardown at disconnect.

>DTn DTMF Detection

n

= 0 or 1

Default: >DT0

Normally, when it goes off-hook, a fax modem ignores tones from the other end of the connection unless
they are fax or modem handshake tones, in which case it responds in kind. The >DT1 command causes
the modem to report DTMF (touch-tone) tones and fax calling tones to software for further processing. A
typical use would be for a program that routes calls to specific communications applications depending on
the type of call or upon a DTMF tone added to a dialing string.

>DT0

disables DTMF detection.

>DT1

enables DTMF detection when the modem goes off-hook.

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