数据通信的基础知识概述

数据通信的基础知识概述

入设备通信。其本地管理接口（LMI）可大大简化帧中继网的配置和管理。

⑤局域网（LAN）与广域网（WAN）的高速连接。

⑥LAN与LAN的互联。

⑦远程计算机辅助设计/制造文件的传送、图像查询以及图像监视、会议电视等

2．无线数据通信的应用

无线数据通信也称为移动数据通信。它的业务范围很广，也有广泛的应

前景。

（1）移动数据通信在业务上的应用。移动数据通信的业务，通常分为基本数据业务和专用数据业务两种：基本数据业务的应用有电子信箱、传真、信息广播、局域网（LAN）接入等。•专用业务的应用有个人移动数据通信、计算机辅助调度、车、船、舰队管理、ＧPS汽车卫星定位、远程数据接入等。

（2）移动数据通信在工业及其它领域的应用。

移动数据通信在这些领域的应用可分为固定式应用、移动式应用和个人应用三种类型。

①固定式应用是指通过无线接入公用数据网的固定式应用系统及网

络。如边远山区的计算机入网、交警部门的交通监测与控制、收费停车场、加油站以及灾害的遥测和告警系统等。

②移动式应用是指野外勘探、施工、设计部门及交通运输部门的运输

车、船队和快递公司为发布指示或记录实时事件，通过无线数据网络实现业务调度、远程数据访问、报告输入、通知联络、数据收集等均需采用移动式数据终端。移动数据终端在公安部门的刑警、巡警、交警也开始应用。

③个人应用是指专业性很强的业务技术人员、公安外线侦察破案人员

等需要在外办公时，通过无线数据终端进行远程打印、传真、访问主机、数据库查询、查证。股票交易商也可以通过无线数据终端随时随地跟踪查询股票信息，即使度假也可以从远程参加股票交易。

Rudimentary knowledge summary of data communication

The communication technology and computer technology that data communication is combine but a kind of new communication way that produce . Must transmit the channel while transmitting information between two places, according to transmitting the difference of medias, difference of wired data communication and wireless data communication. But they all connect data terminal and computer through transmitting the channel , and make the data terminal of different places realize the sharing of software and hardware and information resources.

The pattern of exchanging of data communication and scope of application

1. Usually there are three kinds of patterns of exchanging in data communication for the pattern of exchanging of data communication:

(1) The circuit exchanging

It means two computers or terminal stations are while communicating each other that the circuit exchanges the circuit and exchanges, use the same real physics chain, use this chain to carry on the information transmission from start to finish in communication, allow other computer or terminal station henries of this circuit altogether at the same time.

(2)Newspaper document exchange

newspaper document exchange is it store among memory of exchanger newspaper document of user to exchange (whether memory or outside deposit), as is it when circuit idle , mail exchanger or terminal station received to

need to this newspaper document and then to output while being necessary. This kind of memory - the way to transmit can improve the utilization ratio of junction line and circuit .

(3)Dividing into groups exchanges

it make long data piece on piece to cut whole copies of newspaper document that user send apart into to exchange to divide into groups to exchange to divide into groups (is it divide into groups or bale to call), divide into groups in order to store these - way that transmit transmit in network. The first message of dividing into groups has identifications receiving the address and sending the address in succession . In the packet switching network, different users' grouping data adopt the technology transfer that is replied and used dynamically , namely the network has routes to choose, there can be different users' grouping to convey in the same route, so the utilization ratio of the circuit is relatively high.

2. Scope of application of different patterns of exchanging

(1)Circuit pattern of exchanging apply public telephone network, public telegram network and public datum network(cSPDN) that circuit exchange,etc. among the communication networks usually. Department's traditional way of pattern of exchanging of first two kinds of circuit; The last way and public telephone network are similar basically, but it