[comp.dcom.modems] How to access COM4 using BIOS interrupt 14h?

tcamp@ecsvax.UUCP (Ted A. Campbell) (01/27/88)

I've had relatively good luck in writing simple terminal routines
for PC-compatibles utilizing the BIOS interrupt 14h.  But now
I have an XT clone with 2 serial ports (COM1 and COM2) and an
internal modem attached to COM4.  My old routines don't work,
even when I specify 3 or 4 in the dx register for the BIOS
routines.  Can the BIOS routines work for COM3 and COM4?  What
do I need to do to get to them?  

Thanks in advance.

-- 
Ted A. Campbell       |
Duke Divinity School  |
Durham, NC  27706     |
email:  tcamp@ecsvax  |