baud

baud (bɔːd)
—n
	a unit used to measure the speed of electronic code transmissions, equal to one unit interval per second
[C20: named after J. M. E. Baudot (1845--1903), French inventor]

baud

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 Te'le'graphiques 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.

baud definition

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)