Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site ncrcae.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxb!houxm!whuxl!whuxlm!akgua!mcnc!ncsu!ncrcae!markmc
From: markmc@ncrcae.UUCP (Mark McCulley)
Newsgroups: net.music.synth
Subject: Re: Baud vs bps and more (Wait a minute..??.)
Message-ID: <2116@ncrcae.UUCP>
Date: Thu, 21-Feb-85 19:28:02 EST
Article-I.D.: ncrcae.2116
Posted: Thu Feb 21 19:28:02 1985
Date-Received: Wed, 27-Feb-85 04:10:13 EST
References: <5447@duke.UUCP>
Reply-To: markmc@ncrcae.UUCP
Organization: NCR, Columbia, SC
Lines: 29
Keywords: misconceptions, MIDI and MACintosh
Summary:  I don't think it works quite like this


~From ncsu!mcnc!duke!chan Wed Feb 20 15:25:53 1985
~Subject: Baud vs bps and more

~Baud rate is the number of changes per second.  Thus 9600 baud can transmit
~at 19200 bits per second if each frequency transmitted can represent 2 bits
~of information.
~then a 9600 baud can transmit 19200 bits of information.  So it is possible
~to have RS232 talk to MIDI if somebody can come up with such a protocol.

9600 baud is 9600 characters per second. The bit rate would be ten times
that or 96000 (8 data,one start,one stop).

RS232 *is* a protocol.  MIDI 1.0 specifies a baud rate of 31.25k baud, or
31250 characters per second.  The problem is, this rate is not a standard
with any computer systems (that I know about).  To interface RS232 to MIDI
would require a semi-intelligent buffer, fairly fast too.

~How about using RS422?  It is standard on a Macintosh and as far as I know,
~it can handle serial communication well beyond 32Kbps.  Any suggestion?
~I bring this up just because I have one myself and would like to make use
~of it.

I've thought about this some and there seems to be two approaches.  One would
be with a Appletalk-MIDI device.  The other would involve changing the baud
rate on one channel of the DUART.  I dont' know if the MAC 68000 would be
'real time enough' as it has to handle memory refresh and the video refresh.

mark @.../decvax/mcnc/ncsu/ncrcae/markmc