🚀 go-pugleaf

In article <CHAS.90Dec19185228@tira.uchicago.edu> 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 = <char> - returns status in AH
AH = 2	   ; read char - returns <char> 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."