【正文】 regular intervals are equipped with relay amplification equipment to ensure clear voice. 在這些設(shè)備上若再配置Modem，則能通電話(huà)的地方就可傳輸數(shù)據(jù)。 Configure these devices Ruozai Modem, is to place the phone can transmit data. 一般電話(huà)線(xiàn)路的話(huà)音帶寬在300～3400Hz 范圍，用它傳送數(shù)字信號(hào)，其信號(hào)頻率也必須在該范圍。 Ordinary telephone lines in the 300 ~ 3400Hz voice bandwidth, range, use it to transmit digital signals, the signal must also be in the range of frequencies. 常用的調(diào)制方法有三種:頻移鍵控(FSK)、相移鍵控(PSK) 、相位幅度調(diào)制(PAM)。 There are three monly used methods of modulation: frequency shift keying (FSK), phase shift keying (PSK), phaseamplitude modulation (PAM). Modem通常有三種工作方式:掛機(jī)方式、通話(huà)方式、聯(lián)機(jī)方式。 Usually there are three ways of working Modem: hang up mode, call mode, online. 電話(huà)線(xiàn)未接通是掛機(jī)方式；雙方通過(guò)電話(huà)進(jìn)行通話(huà)是通話(huà)方式；Modem已聯(lián)通，進(jìn)行數(shù)據(jù)傳輸是聯(lián)機(jī)方式。 Telephone line is not connected to hook mode。 both the phone call is a call mode。 Modem had interchange, data transmission is online. 數(shù)模轉(zhuǎn)換的調(diào)制方法有三種： Digitalanalog conversion of the modulation in three ways: (1)頻移鍵控(FS K) ：用特殊的音頻范圍來(lái)區(qū)別發(fā)送數(shù)據(jù)和接收數(shù)據(jù)。 (1) frequency shift keying (FSK): with a special scope to distinguish between audio send data and receive data. 如調(diào)頻ModemBell103型發(fā)送和接收數(shù)據(jù)的二進(jìn)制邏輯被指定的專(zhuān)用頻率是:發(fā)送，信號(hào)邏輯0、頻率1070Hz，信號(hào)邏輯頻率1270Hz；接收，信號(hào)邏輯0、頻率20 25Hz，信號(hào)邏輯頻率2225Hz。 FM ModemBell103 type, such as sending and receiving binary data is designated a special frequency of the logic is: to send the signal logic 0, the frequency of 1070Hz, signal logic 1, the frequency 1270Hz。 receiver, the signal logic 0, Frequency 20 25Hz, the signal logic 1, frequency of 2225Hz. (2)相移鍵控(PSK) ：高速的Modem常用四相制，八相制，而四相制是用四個(gè)不同的相位表示00、011四個(gè)二進(jìn)制數(shù)，如調(diào)相ModemBell212A型。 (2) phase shift keying (PSK): highspeed Modem mon fourphase system, eightphase system, while the fourphase system is expressed in four different phases of four binary numbers 00,01,10,11, such as PM ModemBell212A type. 該技術(shù)可以使3 00bps的Modem傳送600bps的信息，因此在不提高線(xiàn)路調(diào)制速率僅提高信號(hào)傳輸速率時(shí)很有意義，但控制復(fù)雜，成本較高，八相制更復(fù)雜。 The technology allows 3 00bps to 600bps Modem transmission of information, and therefore not only improve the line to improve the signal modulation rate when the transmission rate makes sense, but the control plexity, high cost, eightphase system more plex. (3)相位幅度調(diào)制(PAM) ：為了盡量提高傳輸速率，不提高調(diào)制速率，采用相位調(diào)制和幅度調(diào)制結(jié)合的方法。 (3) phaseamplitude modulation (PAM): In order to maximize the transmission rate, modulation rate does not increase, the phase modulation and amplitude modulation using the method of bining. 它可用16個(gè)不同的相位和幅度電平，使1200bps的Modem傳送19200bps的數(shù)據(jù)信號(hào)。 It can be 16 different phase and amplitude level, so that the Modem 1200bps 19200bps data transmission signal. 該種Modem一般用于高速同步通信中。 The kind of Modem for highspeed synchronous munications generally. 調(diào)制解調(diào)器通電后，通常先進(jìn)入掛機(jī)方式，通過(guò)電話(huà)撥號(hào)撥通線(xiàn)路后進(jìn)入通話(huà)方式，最后通過(guò)Modem的“握手”過(guò)程進(jìn)入聯(lián)機(jī)方式。 Modem is powered, usually the first way into the hook, dial the telephone dialup lines and entered the call, and finally through the Modem39。s handshake process into the online. 正常使用時(shí)，由使用者通過(guò)控制電話(huà)機(jī)或Modem前面板的按鍵、內(nèi)部開(kāi)關(guān)實(shí)現(xiàn)三種方式間的轉(zhuǎn)換。 Normal use, by the user through the phone or Modem front panel control buttons, an internal switch between three ways to achieve the conversion. 調(diào)制解調(diào)器與計(jì)算機(jī)連接是數(shù)據(jù)電路通信設(shè)備DCE（DataCircutterminatingEquipment）與數(shù)據(jù)終端設(shè)備DTE(DataTerminalEquipment)之間的接口問(wèn)題。 Modem and puter to connect the data circuit munications equipment DCE and data terminal equipment DTE the interface between. DCE與DTE之間的接口是計(jì)算機(jī)網(wǎng)絡(luò)使用上的一個(gè)重要問(wèn)題。 DCE and DTE interface between the use of puter networks is an important issue. 任何一個(gè)通信站總要包括DCE與DTE，因此確定一個(gè)統(tǒng)一的標(biāo)準(zhǔn)接口，特別是對(duì)公用數(shù)據(jù)網(wǎng)有重要的意義。 Any munication stations always have to include DCE and DTE, therefore to establish a unified standard interface, especially for public data networks are important. 數(shù)據(jù)終端設(shè)備DTE是產(chǎn)生數(shù)字信號(hào)的數(shù)據(jù)源或接收數(shù)字信號(hào)的數(shù)據(jù)宿，或者是兩者的結(jié)合，像計(jì)算機(jī)終端、打印機(jī)、傳真機(jī)等就是DTE。 DTE data terminal equipment is to produce digital data signal source or receiving digital signal data places, or a bination of both, like puter terminals, printers, fax machines, etc. is DTE. 將數(shù)據(jù)終端設(shè)備DTE與模擬信道連接起來(lái)的設(shè)備就叫數(shù)據(jù)電路通信設(shè)備DCE，像Modem就是DCE。 DTE data terminal equipment connected with the analog channels called data circuit equipment munications equipment DCE, as the Modem is DCE. DTE與DCE之間的連接標(biāo)準(zhǔn)有CC IT ，與EIARS423A兼容，是一種半平衡電氣特性接口 The connection between the DTE and DCE standards CC IT , and EIARS423A patible, is a semibalanced electrical characteristics of interfaces 普通的Modem通常都是通過(guò)RS232C串行口信號(hào)線(xiàn)與計(jì)算機(jī)連接。 Usually through the ordinary Modem RS232C serial port signal lines and puter connections. RS232是一種歷史悠久的計(jì)算機(jī)接口標(biāo)準(zhǔn)。 RS232 is a long history of puter interface standards. （RS本是RemendStandard的縮寫(xiě)），它于1969年被國(guó)際組織認(rèn)可。 (RS RemendStandard this is the abbreviation), which in 1969 recognized by the international organization. RS232的定義包括電氣特性(如電壓值)、機(jī)械特性(如接頭形狀)及功能特性(如腳位信號(hào))等。 RS232 is defined to include electrical features (such as voltage value), mechanical properties (such as joint shape) and functional characteristics (such as the pin signal) and so on. 它允許一個(gè)發(fā)送設(shè)備連接到一個(gè)接收設(shè)備以傳送資料；其原始規(guī)范的最大傳輸速度為20Kbps，但事實(shí)上，現(xiàn)在的應(yīng)用早已遠(yuǎn)超過(guò)這個(gè)速度范圍。 It allows a sending device to a receiving device to send information。 its original specification maximum transmission speed of 20Kbps, but in fact, the present application has already far exceeded the speed range. RS23 2可說(shuō)是相當(dāng)簡(jiǎn)單的一種通信標(biāo)準(zhǔn)，若不使用硬件流控，則最少只需利用三根信號(hào)線(xiàn)，便可做到全雙工的傳輸作業(yè)。 RS23 2 can be a very simple munication standard, if not using hardware flow control, then at least only use three signal lines, can be fullduplex transmission operation. RS232的電氣特性是屬于非平衡傳輸方式，抗干擾能力較弱，故傳輸距離較短，約為15米左右而已。 The electrical characteristics of RS232 is a nonbalanced transmission, antijamming capability is weak, so the transmission distance is shorter, about 15 meters only. RS232C串行口信號(hào)分為三類(lèi)：傳送信號(hào)、聯(lián)絡(luò)信號(hào)和地線(xiàn)。 RS232C serial port signal is divided into three categories: transmission signal, the signal and ground contact. (1)傳送信號(hào)：指TXD(發(fā)送數(shù)據(jù)信號(hào)線(xiàn))和RXD(接收數(shù)據(jù)信號(hào)線(xiàn))。 (1) send a signal: that TXD (transmit data signal line) and RXD (receive data signal lines). 經(jīng)由TXD傳送和RXD接收的信息格式為：一個(gè)傳送單位(字節(jié))由起始位、數(shù)據(jù)位、奇偶校驗(yàn)位和停止位組成。 TXD RXD via transmi