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From: dmt@pegasus.ATT.COM (Dave Tutelman)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Baud vs. bps.
Summary: The rest of the story...
Message-ID: <5001@pegasus.ATT.COM>
Date: 25 Aug 90 14:37:19 GMT
References: <849@idcapd.idca.tds.philips.nl> <4188@trantor.harris-atd.com>
Reply-To: dmt@pegasus.ATT.COM (Dave Tutelman)
Organization: AT&T Bell Labs - Lincroft, NJ
Lines: 32

>In article <849@idcapd.idca.tds.philips.nl> lexw@idca.tds.PHILIPS.nl (Lex Wassenberg) writes:
>>
>>Okay, in some recent articles there were these hints about the difference
>>between "baud" and "bits per second". Now I for one have always thought that
>>baud and bps is the same. So what's the difference? Has it something to do
>>with bits that don't carry actual data like start and stop bits? Or is it
>>more subtle? Thanks to anyone who can inform me (and others).
>>      ________________

In article <4188@trantor.harris-atd.com> sonny@trantor.harris-atd.com (Bob Davis) writes:
>
>	Baud rate and Bit rate are two different things (although they
>are sometimes numerically equal).
>
>THE LIGHTS DIM AS THE LEGEND BEGINS...

... [ excellent discussion of transmission symbols that carry
...   more than one bit ]
... BUT ...

>	THE BIT RATE *ALWAYS* IS EQUAL TO THE BAUD RATE TIMES THE
>	NUMBER OF INFORMATION BITS CARRIED PER BAUD TIME BY THE MODEM.

Close, but not quite. 
Lex's original speculation covers "the rest of the story".

A "bit" is a unit of information.  Start and stop pulses (frequently
and inaccurately called start and stop bits) are really transmission
related synchronizing signals, not information.  The "old" modems
Bob describes actually had a bit rate LESS than the baud rate.

Dave