Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!gatech!ncar!ames!haven!umd5!terminus.umd.edu!dzoey From: dzoey@terminus.umd.edu (Joe Herman) Newsgroups: comp.os.msdos.programmer Subject: Re: Int 14h protocol Message-ID: <7755@umd5.umd.edu> Date: 20 Dec 90 13:24:38 GMT References: Sender: news@umd5.umd.edu Distribution: comp. Organization: University of Maryland DOSIP-CSC Lines: 35 In article chas@tira.uchicago.edu (Charles Blair) writes: > >I would like a description of the Int 14h protocols so that I can >adapt some asynchronous communications software written in 8086 >assembly language to run over Ethernet. Can anyone point me to the >specs? (I already have the telnet driver I need which would grab the >Int 14h I/O.) As long as you have a INT14 interceptor that will send your calls over ethernet (by which I assume you mean TCP/TELNET) the documented INT14 interface is all you need to worry about. The parameters for calling INT14 are documented in the DOS Tech Ref and most books on DOS programming. Here's a thumbnail sketch (from memory) AH = 0 ; Initialize - AL = 0x8 even parity, AL = 0x10 ODD parity AH = 1 ; send char - AL = - returns status in AH AH = 2 ; read char - returns in AL AH = 3 ; status - returns (AH & 1) == 1 if char waiting to be read There are also extended calls AH = 4 & AH = 5. These allow a break to be transmitted as well as a more detailed status of the modem (useless). There are probably return codes that I left out of the above, so you're better off finding a reference in a book. Using INT14 over TCP is a little slow. Running kermit over COMTCP (from the MD-DOSIP package. Sorry had to plug) I get about the equivalent of 9600 baud. Hope this helps, Joe Herman U. of Maryland dzoey@terminus.umd.edu -- "Everything is wonderful until you know something about it."