Baseband
Baseband is used to describe bandwidth and channels (the signal or system frequency). In terms of bandwidth, baseband is the highest frequency (measured in hertz) used by the bandwidth, or the upper bound of the bandwidth.In terms of a channel, baseband is a type of communication channel that uses frequencies that are very close to zero hertz. Serial cables and local area networks (LANs) use baseband channels.
Also see: Bandwidth, Cell phone definitions, Network definitions