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