Path: cantaloupe.srv.cs.cmu.edu!rochester!udel!wupost!gumby!destroyer!cs.ubc.ca!unixg.ubc.ca!erich.triumf.ca!bomr
From: bomr@erich.triumf.ca (Rod Nussbaumer)
Newsgroups: sci.electronics
Subject: Re: multiple inputs for PC
Date: 26 Apr 1993 09:05 PST
Organization: TRIUMF: Tri-University Meson Facility
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Distribution: world
Message-ID: <26APR199309050492@erich.triumf.ca>
References: <93114.142835U19250@uicvm.uic.edu>
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In article <93114.142835U19250@uicvm.uic.edu>, <U19250@uicvm.uic.edu> writes...
>Can anyone offer a suggestion on a problem I am having?
>I have several boards whose sole purpose is to decode DTMF tones and send
>the resultant in ASCII to a PC.  These boards run on the serial interface.
>I need to run * of the boards somwehat simultaneously.  I need to be able to ho
>ok them up to a PC>  The problem is, how do I hook up 8+ serial devices to one
>PC inexpensivley, so that all can send data simulataneously (or close to it)?
>Any help would be greatly appreciated!
>Abhin Singla
If you can modify the design of the DTMF decoder, the ideal comunications
would be over a multi-drop system, like RS-485.  RS-485 boards are available
for PC's, probably cheaper than a bunch of RS-232 channels, and RS-485 is
cheaper to build onto your satellite modules, using only a single supply
8-pin DIP driver chip.  Software at the PC end would be similarly complex
for either RS-232 or RS-485, in my opinion.  The higher data rates possible
with RS-485 would permit quasi-simultaneous data transmission.
Hope this helps.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Rod Nussbaumer, Programmer/Technologist       Bitnet: BOMR@TRIUMFER
  TRIUMF --- University of British Columbia,  Internet: bomr@erich.triumf.ca
  Vancouver, BC, Canada.                         Phone: (604)222-1047 ext 510
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