第十四章Computer Networks.pptVIP

Section 14.1: Data Communication （数据通信） Guidance for your studying: Keywords : find their definition and understand their meaning. Carefully read Fig.14-1 and comprehend it. Write a composition to describe the procession of data communication according to Fig.14-1. (homework) Keywords definitions and usages host Keywords definitions and usages Short for Data Terminal Equipment, a device that controls data flowing to or from a computer. The term is most often used in reference to serial communications defined by the RS-232C standard. This standard defines the two ends of the communications channel as being a DTE and Data Communications Equipment (DCE) device. In practical terms, the DCE is usually a modem and the DTE is the computer itself, or more precisely, the computers UART chip. For internal modems, the DCE and DTE are part of the same device. Keywords definitions and usages Pronounced u-art, and short for universal asynchronous receiver-transmitter, the UART is a computer component that handles asynchronous serial communication. Every computer contains a UART to manage the serial ports, and some internal modems have their own UART. Keywords definitions and usages Short for Data Communications Equipment, a device that communicates with a Data Terminal Equipment (DTE) device in RS-232C communications. See DTE for more information. Keywords definitions and usages Pulse Code Modulation - (PCM) A method by which an audio signal is represented as digital data.A technique for converting analog signals into digital form. Virtually all digital audio systems use PCM, including, CD, DAT, F1 format, 1630 format, DASH, DCC, and MD. Fig.14-1: Simplified block diagram of a data communications link Fig.14-1: Simplified block diagram of a data communications link Fig.14-1: Simplified block diagram of a data communications link Fig.14-1: Simplified block diagram of a data communications link Translation In an interruption, an asset of the system becomes lo