Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!nrl-cmf!cmcl2!brl-adm!umd5!purdue!klinkner
From: klinkner@cs.purdue.EDU (Steven Klinkner)
Newsgroups: comp.sys.ibm.pc
Subject: multiple RS232 ports
Message-ID: <3850@medusa.cs.purdue.edu>
Date: 14 Apr 88 05:26:00 GMT
Sender: news@cs.purdue.EDU
Organization: Department of Computer Science, Purdue University
Lines: 23



I am interested in the possibility of connecting 4 or more communication 
ports to an IBM PC (possible application - multiple-user BBS).  Has 
anyone considered this problem and/or the obstacles involved?  As I see 
it, there are several hurdles:  

- the PC simply may not be fast enough to handle data transfer coupled 
  with significant data processing.  This, however, depends on the 
  application.   

- commercially available RS232 cards interface to IRQ3 & IRQ4.  Is there 
  a SIMPLE was to access the other IRQx lines?  Ignoring other 
  peripherals, you might manage to use 5 lines effectively.  What about 
  more lines?  Do you then design hardware from scratch, multiplexing 
  through one IRQ line?  If so, how do you handle the hardware & 
  software?   

Any ideas or shared experiences would be appreciated.  My interest at 
this point is primarily academic.  

-- 
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                  steve klinkner@hercules.cs.purdue.edu