A communication channel refers to a path, a line or a link that interconnects. A source from which data is sent to its destination where data is to be received. Thus the channel is a “DATA HIGHWAY” which carries the data signals from source to destination. It is a transmission line in a network that move bit between machines communicating over the network
The rate of data transmission based on the number of signal element or symbols transmitted per second is called baud. Bandwidth is measured in bits per second (Bps) also called baud. Baud refers to number of signal changes per second.
Bandwidth is the rang of frequencies that is availble for the transmission of data. We can also say that bandwidth is the amount of data that it can transfer per unit of time.
The data transfer rate: is the speed at which data can be transmitted between devices e.g. Kb per second, Mb per second.
Based an data transmission speeds three basic categories of communication channels (path) as:
Narrow-band or Sub-voice grade channel have speed in the rang of 45 to 300 baud. They are used to handle low data volumes, and are adequate for low speed. They are used mainly for telegraph line and low speed terminals.
Channel have speed up to 9600 baud. They are so called because their major application is in ordinary telephone voice communication.
Channel are used for transmission of larges volumes of data at high speed. They spend of 1 million baud or more broadband futility is used for high-speed computer-to-computer communication.