[comp.dcom.modems] AT&T 4024 Modem DTR help

pete@tsc.DEC.COM (Pete Schmitt) (12/20/87)

How do you you get the DTR to drop on this modem?
It used to drop when I would tell it to with PROCOMM or CTRM,
but now there is nothing I can do to make it drop.  I have
even disconnected the cable, powered it down, then back up.
The dtr comes up without the rs232 cable attached.

Any help out there???


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brian@casemo.UUCP (Brian Cuthie ) (12/21/87)

In article <255@tsc.DEC.COM>, pete@tsc.DEC.COM (Pete Schmitt) writes:
> How do you you get the DTR to drop on this modem?
> It used to drop when I would tell it to with PROCOMM or CTRM,
> but now there is nothing I can do to make it drop.  I have

DTR is Data Terminal Ready and is generated by the DTE equipment (like your
computer) and *not* the modem.  The modem probably has an internal pull-up
on it's DTR input so that it will function with DTE equipment that is connected
only with three wires (2,3,7).

What you want is DSR or DCD.  DSR will show that the modem is powered and
ready while DCD will be true any time the modem is recieving carrier from
another modem (althoug, most modems allow DCD to be optioned several ways).

Give me a call if you still need help.

Cheers,
Brian

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Brian Cuthie
CASE Communications
Columbia, MD 21046
(301) 290 - 7443