baud

from The Collaborative International Dictionary of English v.0.48

baud \baud\ (b[add]d or b[^o]d), n. [Named after J. M. E.
   Baudot, a French inventor, died 1903.] (Computers,
   telecommunications)
   A unit of transmission speed for information conveyed over a
   digital communications channel, usually taken as equal to the
   number of bits of information transmitted per second. The
   speed in bauds indicates the number of signalling events per
   second; however, since it is necessary in most cases to
   transmit control information along with the data, the {data
   signalling rate} may be smaller than the baud rate.
   [PJC]

from Jargon File (4.4.4, 14 Aug 2003)

baud
 /bawd/, n.

   [simplified from its technical meaning] n. Bits per second. Hence
   kilobaud or Kbaud, thousands of bits per second. The technical meaning
   is level transitions per second; this coincides with bps only for
   two-level modulation with no framing or stop bits. Most hackers are
   aware of these nuances but blithely ignore them.

   Historical note: baud was originally a unit of telegraph signalling
   speed, set at one pulse per second. It was proposed at the November,
   1926 conference of the Comite Consultatif International Des
   Communications Telegraphiques as an improvement on the then standard
   practice of referring to line speeds in terms of words per minute, and
   named for Jean Maurice Emile Baudot (1845-1903), a French engineer who
   did a lot of pioneering work in early teleprinters.

from The Free On-line Dictionary of Computing (8 July 2008)

baud
baud rate

   <communications, unit> /bawd/ (plural "baud") The unit in
   which the information carrying capacity or "{signalling rate}"
   of a communication channel is measured.  One baud is one
   symbol (state-transition or level-transition) per second.
   This coincides with bits per second only for two-level
   {modulation} with no {framing} or {stop bits}.

   A symbol is a unique state of the communication channel,
   distinguishable by the receiver from all other possible
   states.  For example, it may be one of two voltage levels on a
   wire for a direct digital connection or it might be the phase
   or frequency of a carrier.

   The term "baud" was originally a unit of telegraph signalling
   speed, set at one {Morse code} dot per second.  Or, more
   generally, the reciprocal of the duration of the shortest
   signalling element.  It was proposed at the International
   Telegraph Conference of 1927, and named after {J.M.E. Baudot}
   (1845-1903), the French engineer who constructed the first
   successful teleprinter.

   The UK {PSTN} will support a maximum rate of 600 baud but each
   baud may carry between 1 and 16 bits depending on the coding
   (e.g. {QAM}).

   Where data is transmitted as {packets}, e.g. characters, the
   actual "data rate" of a channel is

   	R D / P

   where R is the "raw" rate in bits per second, D is the number
   of data bits in a packet and P is the total number of bits in
   a packet (including packet overhead).

   The term "baud" causes much confusion and is usually best
   avoided.  Use "bits per second" (bps), "bytes per second" or
   "characters per second" (cps) if that's what you mean.

   (1998-02-14)