In communications, a system is wideband when the message bandwidth significantly exceeds the coherence bandwidth of the channel. Some communication links have such a high data rate that they are forced to use a wide bandwidth; other links may have relatively low data rates, but deliberately use a wider bandwidth than "necessary" for that data rate in order to gain other advantages; see spread spectrum.

In telecommunications, broadband is wide bandwidth data transmission which transports multiple signals at a wide range of frequencies and Internet traffic types, that enables messages to be sent simultaneously, used in fast internet connections. The medium can be coaxial cable, optical fiber, wireless Internet (radio), twisted pair or satellite.

<communications> A class of communication channel capable of supporting a wide range of frequencies, typically from audio up to video frequencies. A broadband channel can carry multiple signals by dividing the total capacity into multiple, independent bandwidth channels, where each channel operates only on a specific range of frequencies. The term has come to be used for any kind of Internet connection with a download speed of more than 56 kbps, usually some kind of Digital Subscriber Line, e.g. ADSL. A broadband connection is typically always connected, in contrast to a dial-up connection, and a fixed monthly rate is charged, often with a cap on the total amount of data that can be transferred. Domestic broadband connections typically share a telephone line with normal voice calls and the two uses can occur simultaneously without interference. See also baseband, narrowband. (2006-03-30)