🚀 go-pugleaf

 >            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