A data transmission channel carries data from one location to the other and is classified as narrowband, voice band or wideband category. The wider the band, more data it can transmit in a given period of time. Telegraph line are narrowband channels with transmission rate of 5 to 30 characters per second (cps, whereas standard telephone lines are voice band with rate of over 1000cps. Broadband channels are used for higher speeds (over 100,000 cps). Coaxial cables, microwave circuits, and communications satellites are used to provide these broadband channels, Fiber optic cables and laser technology provides broadband channels, cheaper and in large numbers.
In many cases, a terminal operator at a remote station uses a regular dial-up telephone switching network, calls up a number at the CPU location and enters data. When data volume is sufficient, it is economical to acquire dedicated or leased line which can be used both for voice and date purposes by the users like
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10-12-2009, 01:13 AM
Data Transmission
