2 – Basic principles

Publisher Summary This chapter discusses the basic principles of data communication. Every data communications system requires a source of data (a transmitter or line driver), which converts the information into a form suitable for transmission over a link; a receiver that accepts the signal and converts it back into the original data, and a communications link that transports the signals. The communication link can be a copper wire, optical fiber, or a radio/ satellite link. The transmitter and receiver must be able to understand each other for error-free data communication. This requires agreement on a number of factors, including type of signaling used, codes that represent the symbols, and maintaining synchronization between transmitter and receiver. This chapter describes these factors in detail. The chapter also explains the basics of the binary numbering system, including bits, bytes, and characters. It describes the factors that affect transmission speed, such as bandwidth, signal-to-noise ratio, data throughput, and error rate. It explains in detail the basic components of a communication system and describes three communication modes as well as the message format and error detection communication systems. The most common data codes such as Baudot, ASCII, EBCDIC, 4-bit binary code, gray code, and binary coded decimal are explained. The message format and error detection in synchronous communication systems are also described in detail.