Broadband in telecommunications is a term which refers to a signaling method which includes or handles a relatively wide range of frequencies which may be divided into channels or frequency bins.

Broadband is always a relative term, understood according to its context. The wider the bandwidth, the more information can be carried. In radio, for example, a very narrowband signal will carry Morse code; a broader band will carry speech; a yet broader band is required to carry music without losing the high audio frequencies required for realistic sound reproduction. A television antenna described as "normal" may be capable of receiving a certain range of channels; one described as "broadband" will receive more channels.

In data communications a modem will transmit a bandwidth of 64 kilobits per seconds (kbit/s) over a telephone line; over the same telephone line a bandwidth of several megabits per second can be handled by ADSL, which is described as broadband (relative to a modem over a telephone line, although much less than can be achieved over a fibre optic circuit, for example). 

Broadband is a general term for different types of high-speed, high-bandwidth connections to the Internet, including DSL and cable. Broadband channels can carry voice, video, and data simultaneously.

Not all high speed Internet connections use broadband. Some high speed Internet connections are actually dial up services, which do not provide you with suitable speed for good quality Voice over Internet Protocol (VoIP). If you are getting speeds of 90K or better, you are likely to have a broadband connection.

Due to the high speed transmission rates associated with broadband, as opposed to the conventional copper telephone lines.