From a brief communications course the term Baud correctly comes for baudot,
but refers to the individual signal sent down the pipe to the other end.  As
modems developed, they found several ways to increase the number of bits
represented in each signal sent over voice grade lines.  Thus the baud rate
is actually several times less than the corresponding Bits Per Second rate
most generally referred to, and is not easy to determine.  There is a direct
relationship between the actual baud rate and bps.   When there is no modem
involved (direct connect) the baud rate and the bps can be the same.  Bytes
per second is another story, depending on how may bits are in your byte,
sync or async, etc.

Felt like chiming in for a change,
Bob Comeau

-----Original Message-----
From: HP-3000 Systems Discussion [mailto:[log in to unmask]]On
Behalf Of Jeff Kell
Sent: Thursday, December 28, 2000 7:07 PM
To: [log in to unmask]
Subject: Re: [HP3000-L] HBIB vs 19.2kbps speed?


Jeff Woods wrote:

> Baud is definitely more like "bits per second" than "bytes per
> second".  A 300 baud (or bps) asynch connection moves at most 30
> (8-bit) bytes per second (since the 8bits each have one start-bit
> and [usually] one stop-bit, or 10 datacomm bits per byte).

The term "baud" comes from the old "baudot" encoding which, if you
will permit me to bypass thorough reference checks and go on my aging
memory, was a 5 or 6 bit encoding used ages ago for datacomm (forget
the 300 baud, this was when 110 was the rule).  The equations change
a bit with reference to "bytes/sec" or more accurately "chars/sec"

> FWIW, I personally tend to use lower case b to mean "bits" and upper
> case B to mean bytes in most unit abbreviations like these; and that
> capitalization generally is repeated in the rest of the acronym.

I do the same, except there is still an ambiguity between asynchronous
circuits (start/stop bits required) and synchronous (no start/stop) and
still again "network" connections (no start/stop, but framing
overhead).  Then we get a little weirder when talking about things
like a system bus, which is usually in megahertz.  The actual bandwidth
is a factor of the data path on the bus in bits multiplied
by the clock speed of the bus (if it can indeed transmit data on every
clock cycle).

Jeff Kell <[log in to unmask]>