serial information transfer speed with which a modem receives and sends data. The rate equals the number of bits-per-second (BPS) transmitted. The higher the baud rate the faster the speed of transmission but the poorer the transmission on-line quality.
measurement of the speed of a modem, specifically the number of times per second a communications channel changes the carrier signal it sends on the phone line. A 56,000-baud (56K) modem changes the signal 56,000 times a second. Baud is often confused with bits per second ( BPS); technically, they are different measurements.
a unit that measures the speed with which information is transferred. The baud rate is the maximum number of state transitions per second: for instance, a system whose shortest pulses are 1/300 second is operating at 300 baud.
On an RS-232 serial link, the baud rate is equal to the data rate in bits per second (bps).With other kinds of communication, the data rate may be considerably faster than the baud rate. For instance, a 2400- baud modem takes 2400-baud (2400-bps) serial data and encodes it into an audio signal whose true baud rate is 600, near the maximum rate at which a telephone line can transmit pulses. Each pulse carries more than one bit of information. At the receiving end, another modem transforms the signal back into 2400-baud serial data. Using similar techniques, newer modems go as fast as 56,600 baud.

