Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.

Baseband is a transmission method in which direct current pulses are applied directly to the cable to transmit digital signals. The discrete signal consists of either high- or low-voltage pulses that represent binary 1s and 0s or that hold binary information in encoded form. For more information, see "Signals." A baseband network is usually limited to a local area. Ethernet is a baseband network that transmits only one signal at a time.

The direct current signals placed on a baseband transmission system tend to degrade over distance due to attenuation and other factors. In addition, outside interference from electrical fields generated by motors, fluorescent lights, and other electrical devices can further corrupt the signal. The higher the data transmission rate, the more susceptible the signal is to degradation. For this reason, networking standards such as Ethernet specify cable types, cable shielding, cable distances, transmission rates, and other details that must be conformed to in order to guarantee quality service.

Compare baseband to broadband transmission. Most people refer to broadband as any date rate above what can be sent over a telephone circuit. That is 56 Kbits/sec for a standard line or 128 Kbits/sec for ISDN. A broadband system may have its bandwidth divided into channels- some for sending, some for receiving, and some for transmitting different types of information and data.

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