klinkner@cs.purdue.EDU (Steven Klinkner) (04/14/88)
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 cline@pnet01.cts.com (Ben Humphreys) (04/15/88)
Yea...buy SCO XENIX, an 8 port multi-port board, and 8 modems. Then get a
copy of XBBS and the C source and tweak to taste.
UUCP: {cbosgd, hplabs!hp-sdd, sdcsvax, nosc}!crash!pnet01!cline
ARPA: crash!pnet01!cline@nosc.mil
INET: cline@pnet01.CTS.COMwtm@neoucom.UUCP (Bill Mayhew) (04/17/88)
<<what to do about multiple RS232 ports on an XT?>> AT least two aftermarket products come to mind: Arnet and Digiboard. I think that Digiboard has the edge on quality, while it may easer to get Arnet products, since Radio Shark is one of their distributors. The boards use a slave 80188 CPU tightly coupled to 16450 ACIA chips. The 80188 then blops the stuff to the PC via a DMA channel. The board can emulate a COM: port without special driver software. To get the most out of it, you need to run a device driver to support the DMA under DOS. Both of the above boards are supplied with Xenix drivers. There are a lot of other comapnies that make similar products, these are just two that I have happened to use (with an older Compaq 386 and Xenix, that is). --Bill