Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!ub!uhura.cc.rochester.edu!rochester!udel!princeton!cs!elan!sarantos
From: sarantos@elan.Princeton.EDU (Sarantos Kapidakis)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: COM3/IRQ4
Keywords: IRQ4
Message-ID: <6820@rossignol.Princeton.EDU>
Date: 12 Feb 91 07:21:37 GMT
Sender: news@cs.Princeton.EDU
Organization: Princeton University CS Dept
Lines: 23


I have a "2 serial port" card and a modem, and I am wondering what is
the best arrangement for the 3 COM ports.  There are programs that
can use COM3, even when DOS does not recognize it.

The fact that COM1 and COM3 (as well as COM2 and COM4) use the same
IRQ (on their standard configuration), means that I will not be able
to use both of them at the same time (like under Windows), right ?

If yes, then what is the use of having COM3 and COM4 ?

Otherwise, under which circumstances can I use both COM1 and COM3 at
the same time ?  Are there drivers that are needed, or specific
programs (not using IRQs, but only I/O addresses, for example) that
can run in both ports concurrently?  Can you name some ?

Which way will utilize my COM ports better ?
If I get many interesting replies, I'll summarize.

thanks

sarantos
sarantos@princeton.edu