Utp cables are commonly used in local telephone

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Unformatted text preview: gh the number of bits depends upon the communication system used, commonly encountered systems use a total of either 10 or 11 bits per character. Hence a terminal having a speed of 30 characters per second would probably be used with a communication system, which transmits at the rate of 300 bits per second. The communication data transfer rate is measured in a unit called baud. In general usage, baud is identical to bits per second. For instance, a rate of 300 baud is 300 bits per second. Therefore the 30 characters per second terminal would be said to operate at 300 baud. However, technically baud refers to the number of signal (state) changes per second. Thus, using more sophisticated coding techniques, 1 baud can represent 2 or even 3 bits per second. But, with most communication systems, 1 baud represents only one signal change per second and thus is equivalent to 1 bit per second. Depending on their transmission speeds, communication channels (paths) are grouped into three basic categories -narrowband, voiceband, and broadband. Narrowband Narrowband or subvoice grade channels range in speed from 45 to 300 baud. They are used for handling low data volumes and are adequate for low-speed devices. They are used mainly for telegraph lines and low speed terminals. Voiceband Voiceband channels handle moderate data volumes and can transmit data at speeds up to 9600 baud. They are so called because their major application is for ordinary telephone voice communication. They are also used for data transmission from slow I/O devices to CPU or from CPU to slow I/O devices. Moreover, most remote terminals are connected to computers through voiceband channels. Broadband Broadband or wideband-channels are used when large volumes of data are to be transmitted at high speed. These systems provide data transmission rates of 1 million baud or more. A company might use a broadband facility for high-speed computer-to-computer communication or for simultaneous transmission of data to several different devices. As might be expected, the cost of the service increases...
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This document was uploaded on 04/07/2014.

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