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Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!mit-eddie!cybvax0!frog!x!wjr
From: wjr@x.UUCP (Bill Richard)
Newsgroups: net.music.synth
Subject: Re: MIDI and RS232
Message-ID: <426@x.UUCP>
Date: Tue, 12-Mar-85 20:06:13 EST
Article-I.D.: x.426
Posted: Tue Mar 12 20:06:13 1985
Date-Received: Fri, 15-Mar-85 02:33:34 EST
References: <1854@pucc-h> <65@daisy.UUCP>
Organization: Charles River Data Systems, Framingham MA
Lines: 44

{}

I don't know if this it really the right newsgroup for technical
discussions about Baud rate vs bit rate but the following quote is so
confused that I couldn't resist.

In <65@daisy.UUCP> daisy!david says:
> 9600 Baud is not necessarily 9600 bits per second (bps).  Baud measures the
> number of signal changes per second.

So far so good. but,

> For example, a Vadic 1200 Baud modem
> is actually a 1200 bps modem.  The Baud rate is 600 and Vadic puts two bits
> (called a dibit) into each signal change (Baud).  9600 Baud modems are
> actually 9600 bps modems, transmitting at a much lower baud rate.  (Typically,
> they pack three or four bits into each signal change.)

This doen't make any sense. The simplest scheme I know of for encoding
bits into signal changes (NRZ encoding, used by most RS-232 devices)
assigns one signal state to mean 1 and the other to mean 0, giving one
signal change per bit so that bit rate == Baud rate. All other schemes
I know of (FM, MFM, etc.) use more than one signal change to encode
each bit so the bit rate for these encodings is always less that the
Baud rate. I belive that it is theoreticaly impossible to encode more
than one bit into one signal change.

> Please be careful in posting data communications related stuff unless you 
> really know what you are talking about.  People can waste enormous amounts of
> time really easily.  

Agree totally, just look at the time I spent composing this reply. :-)

> The contents of this posting are the
> responsibility of the author who is generally capable of walking and chewing
> gum in near-real time.] 

Have you checked recently? :-)
-- 
----
William J. Richard @ Charles River Data Systems
983 Concord St. Framingham, MA 01701
Tel: (617) 626-1112
uucp: ...!decvax!frog!wjr