Xref: utzoo comp.music:1612 rec.music.synth:14702
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucsd!helios.ee.lbl.gov!pasteur!ames!eos!shelby!neon!news
From: grossman@Sunburn.Stanford.EDU (Stu Grossman)
Newsgroups: comp.music,rec.music.synth
Subject: RS232 <==> MIDI
Message-ID: <1990Jul19.012554.7985@Neon.Stanford.EDU>
Date: 19 Jul 90 01:25:54 GMT
Sender: news@Neon.Stanford.EDU (USENET News System)
Distribution: na
Organization: Computer Science Department, Stanford University
Lines: 26
X-Local-Date: 18 Jul 90 18:25:54 PDT

I am looking for a gadget that will convert between RS232 and MIDI signal
levels.  I want to use this to connect the serial port on a SUN workstation to
some MIDI instruments.  Has anybody out there heard of such a creature?

As I understand it, MIDI runs at 31250 baud, and uses 10 bit frames with eight
data bits, one start and one stop bit.  So far, no problem.  I can program the
Sun to deal with all of that stuff.  The hard part is that MIDI signaling is
1.5 milliamp current loop (balanced or unbalanced?).

If there is a ready-made product for this purpose (at a reasonable price), I
will gladly buy it.  I've checked out some of the interfaces for Macs and PCs.
The Mac interface that I saw seems to take power from the Mac, and did not come
with a pinout diagram.  I don't think that I can get the appropriate power out
of the Sun's serial port, so that means that I would have to get a power supply
and hook it up to the correct pins.  The PC interfaces that I've seen use
plug-in PC boards, which are pretty much useless for me (unless I had a
Sun-386i (which I don't)).  I've haven't been able to look at the interfaces
for the Amiga, perhaps one of them might work?

I'm willing build the interface if I can get hold of an appropriate schematic.
I don't have any knowledge of electronic circuit design, so the schematic had
better not require any (serious) hacking.

Thanks in advance!

		Stu Grossman