Technically, this originally referred to any transmission medium having a bandwidth greater than a traditional telephone (speech) channel (4 kHz). The most common broadband medium is coaxial cable carrying multiple audio, video and data channels simultaneously (though fiber optic cable is increasingly common for digital transmission). Each channel takes up a different frequency on the cable. There are guard bands, or empty spaces, between the channels to make sure each channel does not interfere with its neighbor. The most common example is CATV cable, more commonly known as cable TV. Some argue that to be “broadband” the medium must support frequencies up to 20 kHz. These days the term broadband can mean different things depending upon the exact context, but the general understanding is that it refers to a signal or signal carrying device capable of handling a relatively large amount of information. For example, in computing, “broadband” is generally applied to the ability to transfer large amounts of data at high speed.