Path: utzoo!attcan!uunet!abcfd20.larc.nasa.gov!ipsun.larc.nasa.gov!jcburt
From: jcburt@ipsun.larc.nasa.gov (John Burton)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Networking Software Needed
Message-ID: <1990Nov2.164156.26113@abcfd20.larc.nasa.gov>
Date: 2 Nov 90 16:41:56 GMT
References: <1913@shodha.enet.dec.com>
Sender: news@abcfd20.larc.nasa.gov (USENET File Owner)
Organization: NASA Langley Research Center, Hampton, VA  USA
Lines: 49

In article <1913@shodha.enet.dec.com> wood@drift.dec.com (John F. Wood) writes:
>
>I am looking for networking software to allow an IBM PC to connect to
>several (1-30) remote micro-controllers using a single serial port.  The
>software needs to allow for individual messages to be sent from and received
>by the PC.  I will need to write the compatible software for the
>micro-controllers (which currently use Intel 8051 microprocessors), so the
>protocol specs must be provided with the PC software.
>
>While I can (and have) implemented simple software to do some of this, I
>would like to find software that has already implemented error checking in
>all (or most) of its various forms, as well as the multiple remote support.
>
>The communications can either be done via polling the remotes, or by a
>collision detect scheme similar to that employed by Ethernet.  The
>electrical connection will be RS-485 which allows multiple devices on a
>single line.
>
>I've seen several network packages which implement file transfer and remote
>device support between PCs, but I'm not familiar with any that allow
>programmers to send individual messages.  The PC needs to be able to act as
>a central control facility, data storage device, and master scheduler for
>the remotes, through my programming.
>
>FYI, the application is adding intelligence to a house with distributed
>controllers interfaced to many different sub-systems.
>
>Any ideas?
>
>Thanks,
>
>John
>

I know this probably won't help much, but another possibility is
to go with another interface instead of the serial line. 
The serial port on a PC is not really designed to do what you want to
do efficiently. The IEEE-488 (or GPIB) interface is commonly used for 
controlling several pieces
of lab equipment from a single PC. This particular interface was designed
to do what you're trying to do, one master machine controlling several
slave machines. Several companies manufacture entire product lines
for just this purpose. Two that come to mind right away are Data Translation
and Metra Byte Corp. I've never done business with  either (in the past
few years) but it might be worth your time to look into it. 

John Burton
(jcburt@cs.wm.edu)
(jcburt@ipsun.larc.nasa.gov)