From: joan_alb AT arrakis DOT es
Newsgroups: comp.os.msdos.djgpp
Subject: Modem programming question
Date: Thu, 17 Jul 1997 14:59:02 GMT
Message-ID: <33ce2c3e.62659@news.arrakis.es>
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To: djgpp AT delorie DOT com
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 Hi there,

 I've got a serial-comm library, which is working very well. Now I
 want to enhance it adding Modem-to-Modem calls, and I'm not much
 sure about the exact steps needed. These are the ones I suppose:

 1- User A dials the phone number (sending the command "ATDT..." to
     his Modem)
 2- User B checks for the ring signal (a bit of the Modem Status Register).
     When he detects it, he tells his Modem to answer the incoming call
     ("ATA"). He also raises the DTR line.
 3- User A sees the Carrier Detected bit of the UART, and raises DTR.
 4- At this point, both users can send/receive bytes as they would over
     a direct serial conection.
 5- When any of them wants to terminate the connection, lowers DTR and
     tells the Modem to hang up ("H0"). The other user detects it (no    
     carrier?) and does the same.


 I tried to find this list in a Modem FAQ, but wasn't able. So any 
 corrections/enhancements you could make me would be really
 appreciated, as I'm afraid the question it's harder than this.

 (E-mail replies preferred). Thanks,


       Joan-Albert
       joan_alb AT arrakis DOT es