一個(gè)Linux下基于電話線路的數(shù)據(jù)通信程序的設(shè)計(jì)與實(shí)現(xiàn)

論文字?jǐn)?shù):13807,頁(yè)數(shù):29

摘    要
本設(shè)計(jì)基于Linux操作系統(tǒng)，控制本地MODEM通過(guò)電話線網(wǎng)向異地終端機(jī)所帶MODEM撥號(hào)，并實(shí)現(xiàn)兩臺(tái)MODEM之間數(shù)據(jù)傳輸，達(dá)到兩臺(tái)計(jì)算機(jī)之間數(shù)據(jù)通信的目的。 MODEM與計(jì)算機(jī)RS-232串行端口相連，Linux通過(guò)POSIX termios接口控制計(jì)算機(jī)串行端口，方便實(shí)現(xiàn)了對(duì)計(jì)算機(jī)串行端口的設(shè)置和數(shù)據(jù)讀寫。計(jì)算機(jī)(DTE)與MODEM(DCE)之間數(shù)據(jù)交換，以及計(jì)算機(jī)對(duì)MODEM的控制，就是計(jì)算機(jī)對(duì)串行端口的讀寫。
本文作者完成了對(duì)RS-232串行端的設(shè)置和讀寫操作，利用AT命令控制MODEM撥號(hào)，和一個(gè)文件傳輸協(xié)議，實(shí)現(xiàn)了兩臺(tái)PC機(jī)利用MODEM通過(guò)公用電話網(wǎng)，傳送和接收文件。本設(shè)計(jì)旨在使沒(méi)有安裝網(wǎng)絡(luò)的用戶，利用56K MODEM，通過(guò)電話線網(wǎng)方便和對(duì)方傳輸數(shù)據(jù)。相比較Internet網(wǎng)絡(luò)，電話線網(wǎng)更安全，分布更廣泛。本設(shè)計(jì)就是利用了電話線網(wǎng)的廣泛性和安全性。

關(guān)鍵詞：Linux；串行端口；MODEM

The Design and Implementation of Data Transportation through Telephone Line in Linux
Abstract
The purpose of the design is to control the local MODEM to dial remote terminal by telephone line base on Linux operating system. At the same time,it can make the data transmit between two MODEMs to achieve the purpose of data transportation. the MODEM is connected to the computer through the serial port RS-232. Linux can control the serial port of the computer by POSIX termios interface. That can carry out the setting and data reading/writing of the serial port, the data transmit between computers (DTE) and MODEM (DCE), and the control from the computer to the MODEM, namely, the reading/writing of the serial port from the computer.
The author of this paper accomplishes the setting and reading/writing operation, using the AT commands to control the MODEM dialing, and a transport protocols for files. All of these make two PCs send and receive files from the public telephone line by using the MODEM. The design is intended to make the user who has not installed the network to transmit data with others by telephone lines using the 56k MODEM. Compared with the Internet, the telephone line is safer and widely distributed. The design makes use of the universality and the safety of the telephone line.

Key words: Linux; serial port; MODEM

目  錄

1 引  言 2
1.1 設(shè)計(jì)背景 2
1.2 本設(shè)計(jì)的意義 2
1.3 設(shè)計(jì)方法 2
1.4 理論依據(jù) 2
2 設(shè)計(jì)理論依據(jù) 2
2.1 Linux 2
2.2 串行端口簡(jiǎn)介 2
2.2.1 串行通迅 2
2.2.2 RS-232-C 2
2.2.3 異步通迅 3
2.3 MODEM簡(jiǎn)介 4
2.3.1 MODEM 4
2.3.2 AT命令 4
3 系統(tǒng)開(kāi)發(fā)環(huán)境 5
3.1 系統(tǒng)開(kāi)發(fā)環(huán)境 5
3.2 gcc簡(jiǎn)介 5
4 程序的設(shè)計(jì) 6
4.1 設(shè)計(jì)概要 6
4.2 RS-232-C建立與打開(kāi) 7
4.3 串口設(shè)置與讀寫 8
4.3.1 c_cflag控制項(xiàng)設(shè)置 8
4.3.2 c_iflag、c_lflag和c_oflag設(shè)置 9
4.3.3 c_cc控制字符設(shè)置 10
4.3.4 讀寫串口 11
4.4 MODEM的控制 12
4.4.1 MODEM的兩種工作狀態(tài) 12
4.4.2 DTE與DCE的握手 12
4.4.3 MODEM撥號(hào)連接 13
4.5 文件傳輸協(xié)議的設(shè)計(jì) 14
5 編碼實(shí)現(xiàn) 16
5.1 串口初始化實(shí)現(xiàn) 16
5.2 串口讀寫的實(shí)現(xiàn) 17
5.3 MODEM初始化的實(shí)現(xiàn) 18
5.4 MODEM狀態(tài)讀取的實(shí)現(xiàn) 20
6 程序測(cè)試 20
6.1 串口傳輸文件測(cè)試 20
6.2 MODEM撥號(hào)連接并傳輸數(shù)據(jù)測(cè)試 21
結(jié)    論 21
參考文獻(xiàn) 22
致    謝 23
聲    明 24