Baud is a unit of measurement for data transmission speed that represents the number of signal changes, or symbols, transmitted per second.
In communication systems, baud rate refers to how many signal symbols are transmitted per second along a channel. While sometimes equated with bits per second (bps), baud and bit rate are not always the same. In simple encoding, one baud equals one bit, but in advanced modulation schemes, each signal change can represent multiple bits. For example, 9,600 baud may equal 9,600 bps in basic systems or 19,200 bps or more with complex encoding. Baud rate is critical in serial communications such as RS-232, RS-485, and BACnet MS/TP, where transmission speed directly affects system performance. Although modern networking often emphasizes data rate and throughput, baud remains foundational for evaluating low-speed or legacy communication systems used in building automation and industrial controls.
Baud rates in communication systems may fall under IEEE (Institute of Electrical and Electronics Engineers) and TIA (Telecommunications Industry Association) standards, especially for serial communication protocols and physical layer specifications.
The term “baud” is named after Émile Baudot, a French telegraph engineer from the late 19th century who pioneered digital telegraphy. His innovations laid the groundwork for modern signaling measurement in data communications.