Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/5/84; site cvl.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!panda!talcott!harvard!seismo!umcp-cs!cvl!hsu
From: hsu@cvl.UUCP (Dave Hsu)
Newsgroups: net.music.synth
Subject: Re: Re: MIDI
Message-ID: <102@cvl.UUCP>
Date: Wed, 27-Feb-85 17:44:42 EST
Article-I.D.: cvl.102
Posted: Wed Feb 27 17:44:42 1985
Date-Received: Sat, 2-Mar-85 03:20:30 EST
References: <3416@alice.UUCP> <8617@brl-tgr.ARPA>
Organization: Computer Vision Lab, U. of Maryland, College Park
Lines: 16

> > Also, as Dave Hsu pointed out,
> > the MIDI standard requires a current loop interface, hence an opto-
> > isolator.
> > 
> 
> Eh?  The schematics for the MPU show the lines to be balanced pairs.
> They are driven by convetional drivers, no optoisolaters are involved.
> 
> -Ron

Refer to David Dronan's Exploring MIDI: the Musical Instrument Digital
Interface.  The spec calls for a 5ma current loop interface.  How the
Macintosh can accomplish an interface with NO MORE THAN A CABLE would be
my next question.  How is the Mac capable of handling current loops?

-dave