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From: Norbert_Unterberg@p4.f36.n245.z2.fidonet.org (Norbert Unterberg)
Newsgroups: comp.windows.ms.programmer
Subject: Re: Modem Hangup from inside Win 3.0 App
Message-ID: <1602934125@p4.f36.n245.z2.fidonet.org>
Date: 31 May 91 09:52:00 GMT
Article-I.D.: p4.1602934125
References: <7334@p1.f6.n242.z2.fidonet.org>
Reply-To: Norbert_Unterberg%p4.f36.n245.z2@hippo.dfv.rwth-aachen.de (Norbert Unterberg)
Organization: Point of SoftStream, Dortmund, Germany
Lines: 30
Comment-To: _Bruce_Oneel_@f1.n6000.z2.fidonet.org (Bruce Oneel)


 >            I am writing a Windows 3.0 application that is utilizing
 >    a modem to access a database system, download data and then
 > terminating
 >    the connection.  I can not get the application to hang up the modem
 >    after the data transfer is complete.  I need a way to drop DTR from
 >    inside the Windows application.  If anyone has experienced this
 >    problem and has a way to do it, I would be most thankful.  I have
 >    tried to get the modem attention by send +++ and waiting for the
 >    string OK, but on a 2400 baud modem this does not seem to work.

Windows provides an easy way to manage the signals DTR and RTS. Just use 
EscapeCommFunction(nCid, CLRDTR).

Your other problem: As far as I know, +++ places the modem into the the command 
mode, but it does not answer with "OK". Try the following:

 - Flush the output buffer or wait until it is empty. (important!)
 - Wait for 2 seconds
 - Send a "+++" (without CR)
 - Wait for output buffer empty
 - Wait for 2 seconds
 - Send "AT" followed by a CR.

Now the modem should respond with an "OK" string and can safely assumed to be 
in command mode.

Norbert
Dortmund, Germany