Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!dev0d.mdcbbs.com!pirk
Newsgroups: comp.music
Subject: Re: Rs-232 to MIDI (second try) :-)
Message-ID: <1991May14.162730.1@dev0d.mdcbbs.com>
From: pirk@dev0d.mdcbbs.com
Date: 14 May 91 16:27:30 GMT
Organization: McDonnell Douglas M&E, Cypress CA
Nntp-Posting-Host: dac
Nntp-Posting-User: sam
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** Excuse the double post, but it seems that the edit buffer did not include
   any changes to the previous followup.

In article <2679@fornax.UUCP>, troy@fornax.UUCP (Troy Brooks) writes:
> I'm trying to find an RS-232 to MIDI interface to connect to the 
> Silicon Graphics Personal Iris workstations here in the graphics
> research lab. Ultimately we want to be able to play back MIDI
> sequences from within our animation software. The IBM interfaces
> (MPU - 401 ?) don't use RS-232 because the baud rate is too slow on
> PCs. (9600 baud). So, if I can't find one, I'll have to build one,

	The conversion you mention consists of baud rate and hardware
differences.  The baud rate for midi is not one of the normal rs-232
"standards" (I believe it is around 39Kbaud) and the electrical connections 
are isolated using opto couplers on the input.  
	Look into some back issues of Electronic Musician and you will find 
article about the design of the "correct"  or new and improved midi volume
fader project (feb. or march '91).  This project uses an Intel 8031 micro to
act as a midi data stream traffic cop with lots of room for expansion.  
One possible application would be to read the midi data stream and shove all 
the incoming data into the Iris via a parallel port if it is bidirectional
(or serial if not worried about throughput).  
	If you want serial, have the 8031 convert the data to 38.4Kbaud and 
keep your fingers crossed.  BTW, if you can use the parallel port, all outgoing 
data is treated as memory read/writes and placed in the 8031's serial buffer 
for automatic transmission.
	Also, check with Black Box Corp., they would be able to do it, but will
cost a few bucks....

Steve
-- 
 
.Steve Pirk.......midit.....Voice: (714) 952-5516.........................
..McDonnell Douglas M&E..Internet: pirk@dev0d.mdcbbs.com..................
...5701 Katella Ave..........UUCP: uunet!mdcbbs!dev0d.mdcbbs!pirk.........
....Cypress, CA. 90630........PSI: PSI%31060099980019::DEV0D::PIRK........
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"The opinions expressed herein, are probably not those of MDC, and I'm not
 sure if I can even call them mine......." 
 
-- 
 
.Steve Pirk.......midit.....Voice: (714) 952-5516.........................
..McDonnell Douglas M&E..Internet: pirk@dev0d.mdcbbs.com..................
...5701 Katella Ave..........UUCP: uunet!mdcbbs!dev0d.mdcbbs!pirk.........
....Cypress, CA. 90630........PSI: PSI%31060099980019::DEV0D::PIRK........
--------------------------------------------------------------------------
"The opinions expressed herein, are probably not those of MDC, and I'm not
 sure if I can even call them mine......."