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<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62501a1374bc5c01055afd88/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">R<span class="ls1">S<span class="ls2">232<span class="_"> </span><span class="ff2 ls3">技<span class="ls2">术</span>文摘</span><span class="ls4"> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ff2 ls3">枕<span class="ls2">善</span>居<span class="ls2">收</span>集<span class="ls2">整理</span></span><span class="ls5"> </span> <span class="ls5"> </span> <span class="ls3">h<span class="ls6">t<span class="ls7">t</span></span></span></span>p<span class="ls8">:<span class="ls6">//<span class="ls9">ww<span class="lsa">w<span class="lsb">.<span class="ls7">m<span class="ls3">n</span></span></span></span></span></span></span>d<span class="lsc">s<span class="ls3">o<span class="lsd">f<span class="ls6">t.<span class="lse">c</span></span></span>om </span></span></span></span></div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 lsd ws0">-<span class="lsb"> <span class="ls2">1</span> </span>- </div><div class="t m0 x1 h3 y3 ff3 fs1 fc1 sc0 ls2 ws0"> <span class="ff2 fs2 fc2">版<span class="ls3">权</span>声明<span class="lsf">：</span>本资<span class="ls3">料</span>来自互<span class="ls3">联</span>网<span class="lsf">，</span>枕善<span class="ls3">居</span>只负<span class="ls3">责</span>聚合<span class="lsf">，</span>原版权<span class="ls3">规</span>原作者<span class="ls3">所有<span class="_ _0"></span><span class="ff4">!</span></span>枕<span class="ls3">善</span>居不</span></div><div class="t m0 x3 h4 y4 ff2 fs2 fc2 sc0 ls2 ws0">负责任何<span class="ls3">责</span>任！<span class="_ _1"></span><span class="ff4"> (<span class="ff2 ls3">我<span class="ls2">为人人<span class="ls10">，</span></span>人<span class="ls2">人为我<span class="ls10">，</span></span>枕<span class="ls2">善居</span></span> ht<span class="ls3">t</span>p://www.mn<span class="ls3">d</span>soft.co<span class="ls3">m) </span></span></div><div class="t m0 x1 h3 y5 ff3 fs1 fc1 sc0 ls3 ws0"> </div><div class="t m0 x4 h5 y6 ff5 fs3 fc0 sc1 ls3 ws0">目<span class="ff3 sc0 ls11"> <span class="ls12"> </span></span><span class="ls12">次<span class="ff3 sc0"> </span></span></div><div class="t m0 x5 h6 y7 ff3 fs2 fc1 sc0 ls12 ws0"> </div><div class="t m0 x6 h4 y8 ff4 fs2 fc3 sc0 ls2 ws0">1.<span class="ff6"> <span class="_ _2"> </span></span>RS-232-C<span class="_ _3"> </span><span class="ff2 ls3">详解</span> <span class="ff2 ls3">…<span class="ls2">………</span>…<span class="ls2">………</span>…<span class="ls2">………</span>…<span class="ls2">…</span>…<span class="ls2">…………</span>……<span class="_ _0"></span></span>2 </div><div class="t m0 x6 h4 y9 ff4 fs2 fc3 sc0 ls2 ws0">2.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">串口通信<span class="ls3">基</span>本接线<span class="ls3">方法</span></span></span> <span class="ff2">…<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……<span class="_ _0"></span></span></span>12 </div><div class="t m0 x6 h4 ya ff4 fs2 fc3 sc0 ls2 ws0">3.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">串口通讯<span class="ls3">的</span>概念及<span class="ls3">接</span>口电路</span></span> <span class="ff2">………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span></span>13 </div><div class="t m0 x6 h4 yb ff4 fs2 fc3 sc0 ls2 ws0">4.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">有关<span class="_ _3"> </span></span></span>RS232<span class="_ _3"> </span><span class="ff2">和<span class="_ _3"> </span></span>RS485<span class="_ _4"></span><span class="ff2">接口的<span class="ls3">问答</span></span> <span class="ff2">…<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……<span class="_ _0"></span></span></span>14 </div><div class="t m0 x6 h4 yc ff4 fs2 fc3 sc0 ls2 ws0">5.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">同步通信<span class="ls3">方式</span></span></span> <span class="ff2">…<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……<span class="_ _0"></span></span></span>16 </div><div class="t m0 x6 h4 yd ff4 fs2 fc3 sc0 ls2 ws0">6.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">通信协议<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span></span></span>19 </div><div class="t m0 x6 h4 ye ff4 fs2 fc3 sc0 ls2 ws0">7.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">实战串行<span class="ls3">通</span>讯……<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span></span></span>25 </div><div class="t m0 x6 h4 yf ff4 fs2 fc3 sc0 ls2 ws0">8.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">全双工和<span class="ls3">半</span>双工方式</span></span><span class="ls3"> </span><span class="ff2">……<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……<span class="_ _0"></span></span></span>33 </div><div class="t m0 x6 h4 y10 ff4 fs2 fc3 sc0 ls2 ws0">9.<span class="ff6"> <span class="_ _2"> </span><span class="ff2">浅析<span class="_ _3"> </span></span></span>PC<span class="_ _3"> </span><span class="ff2">机<span class="ls3">串</span>口通讯<span class="ls3">流</span>控制</span> <span class="ff2 ls3">…<span class="ls2">………</span>…<span class="ls2">………</span>…<span class="ls2">…</span>…<span class="ls2">…………</span>……</span>34 </div><div class="t m0 x6 h4 y11 ff4 fs2 fc3 sc0 ls2 ws0">10.<span class="ff6"> <span class="_ _4"> </span><span class="ff2">奇偶校验</span></span> <span class="_ _5"></span><span class="ff2">………<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span><span class="ff4">35 </span></span></div><div class="t m0 x6 h4 y12 ff4 fs2 fc3 sc0 ls2 ws0">11.<span class="ff6"> <span class="_ _4"> </span><span class="ff2">开发通信<span class="ls3">软</span>件的技<span class="ls3">术</span>与技巧</span></span> <span class="_ _5"></span><span class="ff2">………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span><span class="ff4">36 </span></span></div><div class="t m0 x6 h4 y13 ff4 fs2 fc3 sc0 ls2 ws0">12.<span class="ff6"> <span class="_ _4"> </span><span class="ff2">接口技术<span class="ls3">的</span>基本知识</span></span><span class="ls3"> </span><span class="ff2">……<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……<span class="_ _0"></span></span></span>41 </div><div class="t m0 x6 h4 y14 ff4 fs2 fc3 sc0 ls2 ws0">13.<span class="ff6"> <span class="_ _4"> </span><span class="ff7">一个单片<span class="ff2 ls3">机<span class="ls2">串行</span></span>数<span class="ls3">据采<span class="ff2">集<span class="_ _0"></span><span class="ff4">/<span class="_ _0"></span></span></span></span>传<span class="ls3">输</span>模块<span class="ff2">的</span><span class="ls3">设计<span class="ff4"> <span class="_ _0"></span></span></span><span class="ff2">…<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span></span></span></span>44 </div><div class="t m0 x6 h4 y15 ff4 fs2 fc3 sc0 ls2 ws0">14.<span class="ff6"> <span class="_ _4"> </span><span class="ff7">单<span class="ff2">工</span>、<span class="ff2">半<span class="ls3">双</span>工和全<span class="ls3">双</span>工的</span>定义</span></span><span class="ls3"> </span><span class="ff2">……<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……<span class="_ _0"></span></span></span>48 </div><div class="t m0 x6 h4 y16 ff4 fs2 fc3 sc0 ls2 ws0">15.<span class="ff6"> <span class="_ _4"> </span><span class="ff7">从<span class="_ _3"> </span></span></span>RS232<span class="_ _3"> </span><span class="ff7">端<span class="_ _5"></span><span class="ff2">口<span class="ff7">获得</span>电<span class="ff7">源</span>……<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span><span class="ff4">49 </span></span></span></div><div class="t m0 x6 h4 y17 ff4 fs2 fc3 sc0 ls2 ws0">16.<span class="ff6"> <span class="_ _4"> </span><span class="ff2">串行同步<span class="ls3">通</span>信的<span class="ff7">应用<span class="_ _5"></span><span class="ff2">………<span class="ls3">…</span>………<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span><span class="ff4">50 </span></span></span></span></span></div><div class="t m0 x6 h4 y18 ff4 fs2 fc3 sc0 ls2 ws0">17.<span class="ff6"> <span class="_ _4"> </span><span class="ff2">串行通信<span class="ff7 ls3">波<span class="ls2">特率</span></span>的<span class="ff7 ls3">一种<span class="ff2">自<span class="_ _0"></span></span><span class="ls2">动</span>检测<span class="_ _0"></span></span>方法<span class="ls3">…</span>………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span></span></span>53 </div><div class="t m0 x6 h4 y19 ff4 fs2 fc3 sc0 ls2 ws0">18.<span class="ff6"> <span class="_ _4"> </span></span>RS-232<span class="ff7">、</span>RS-<span class="_ _5"></span>422<span class="_ _3"> </span><span class="ff2">与<span class="_ _3"> </span></span>RS-485<span class="_ _4"> </span><span class="ff7 ls3">标准<span class="_ _0"></span><span class="ff2">及<span class="_ _0"></span></span><span class="ls2">应用<span class="_ _5"></span><span class="ff2">………<span class="ls3">…</span>…<span class="ls3">…</span>…………<span class="ls3">……</span><span class="ff4">56 </span></span></span></span></div><div class="t m0 x6 h4 y1a ff4 fs2 fc3 sc0 ls2 ws0">19.<span class="ff6"> <span class="_ _4"> </span><span class="ff2">串口<span class="ff7">泵</span></span></span> <span class="ff2 ls3">…<span class="ls2">………</span>…<span class="ls2">………</span>…<span class="ls2">………</span>…<span class="ls2">………</span>…<span class="ls2">…</span>…<span class="ls2">…………</span>……</span>64 </div><div class="t m0 x1 h3 y1b ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y1c ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y1d ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y1e ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y1f ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y20 ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y21 ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y22 ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y23 ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y24 ff8 fs1 fc1 sc0 ls2 ws0"> </div><div class="t m0 x1 h3 y25 ff8 fs1 fc1 sc0 ls2 ws0"> </div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.613445,0.000000,0.000000,1.613445,0.000000,0.000000]}'></div></div>
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<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62501a1374bc5c01055afd88/bg2.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">R<span class="ls1">S<span class="ls2">232<span class="_"> </span><span class="ff2 ls3">技<span class="ls2">术</span>文摘</span><span class="ls4"> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ff2 ls3">枕<span class="ls2">善</span>居<span class="ls2">收</span>集<span class="ls2">整理</span></span><span class="ls5"> </span> <span class="ls5"> </span> <span class="ls3">h<span class="ls6">t<span class="ls7">t</span></span></span></span>p<span class="ls8">:<span class="ls6">//<span class="ls9">ww<span class="lsa">w<span class="lsb">.<span class="ls7">m<span class="ls3">n</span></span></span></span></span></span></span>d<span class="lsc">s<span class="ls3">o<span class="lsd">f<span class="ls6">t.<span class="lse">c</span></span></span>om </span></span></span></span></div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 lsd ws0">-<span class="lsb"> <span class="ls2">2</span> </span>- </div><div class="t m0 x1 h3 y26 ff8 fs1 fc1 sc0 lsd ws0"> </div><div class="t m0 x1 h4 y27 ff4 fs2 fc1 sc0 lsd ws0"> </div><div class="t m0 x1 h3 y28 ff3 fs1 fc1 sc0 ls2 ws0">RS-232-C<span class="_ _6"> </span><span class="ff5 sc2">详解</span><span class="ff9 fs2"> </span></div><div class="t m0 x7 h4 y29 ff2 fs2 fc3 sc0 ls2 ws0">串行通信<span class="ls3">接口</span><span class="ff7">标准<span class="ls3">经</span>过使用</span><span class="ls3">和发<span class="_ _0"></span><span class="ff7">展<span class="_ _0"></span></span>，<span class="_ _7"></span><span class="ff7">目<span class="ls2">前已经<span class="ff2">有</span>几</span>种<span class="ls13">。<span class="ls2">但都是在<span class="_ _4"> </span><span class="ff4">RS-232<span class="_ _4"> </span></span>标准<span class="ff2">的基</span>础上</span></span></span></span></div><div class="t m0 x1 h4 y2a ff7 fs2 fc3 sc0 ls2 ws0">经过改进<span class="ls3">而</span>形成<span class="ff2">的</span>。<span class="_ _8"></span><span class="ff2">所<span class="ff7">以</span>，<span class="_ _8"></span><span class="ff7">以<span class="_ _4"> </span><span class="ff4">RS-232C<span class="_ _3"> </span><span class="ff2">为</span></span>主<span class="ff2">来</span><span class="ls3">讨</span>论。<span class="_ _8"></span><span class="ff4 ls3">RS-<span class="_ _0"></span><span class="ls2">323C<span class="_ _3"> </span><span class="ff7">标<span class="ls3">准</span>是美国<span class="_ _3"> </span></span>E</span>I<span class="ls2">A(<span class="ff2">电<span class="ff7">子</span>工<span class="ff7">业</span>联合</span></span></span></span></span></div><div class="t m0 x1 h4 y2b ff7 fs2 fc3 sc0 ls2 ws0">会）<span class="ff2">与<span class="_ _3"> </span><span class="ff4">BELL<span class="_ _4"> </span></span></span>等公司<span class="ls3">一起<span class="_ _0"></span></span><span class="ff2">开<span class="ls3">发的<span class="_ _6"> </span></span><span class="ff4">1969<span class="_ _3"> </span></span></span><span class="ls3">年</span>公布<span class="ff2">的<span class="ls3">通</span>信<span class="ls3">协议</span></span>。它适<span class="ff2">合</span>于数据<span class="ls3">传</span>输速率在<span class="_ _4"> </span><span class="ff4">0</span>～</div><div class="t m0 x1 h4 y2c ff4 fs2 fc3 sc0 ls2 ws0">20000b/s<span class="_ _3"> </span><span class="ff7 ls3">范<span class="ls2">围内<span class="ff2">的<span class="ls3">通信</span></span>。这</span>个<span class="ls2">标准对</span><span class="ff2">串<span class="ls2">行通信</span>接<span class="ls2">口</span>的<span class="ls2">有关问<span class="ff7">题</span>，<span class="ff7">如</span>信<span class="ff7">号</span>线<span class="ff7">功能、</span>电<span class="_ _5"></span><span class="ff7">器特性</span></span></span></span></div><div class="t m0 x1 h4 y2d ff7 fs2 fc3 sc0 ls2 ws0">都<span class="ff2">作</span>了<span class="ff2">明</span>确<span class="ff2">规</span>定<span class="ls14">。</span>由于<span class="ff2 ls3">通行</span>设备<span class="ls3">厂</span>商都生产<span class="ff2">与<span class="_ _4"> </span><span class="ff4">RS-23<span class="ls3">2C<span class="_ _6"> </span></span></span>制式</span>兼容<span class="ff2 ls3">的<span class="ls2">通信</span><span class="ff7">设备<span class="_ _0"></span></span>，<span class="_ _8"></span><span class="ffa ls2">因此<span class="ff2">，<span class="_ _8"></span><span class="ff7">它<span class="ff2">作为</span></span></span></span></span></div><div class="t m0 x1 h4 y2e ff7 fs2 fc3 sc0 ls2 ws0">一种标准<span class="ff2">，</span>目前已在<span class="_ _5"></span><span class="ffa">微<span class="ff2">机通<span class="ls3">信</span>接口</span>中<span class="ls3">广泛</span><span class="ff7">采用。<span class="ff4"> <span class="fc0"> </span></span></span></span></div><div class="t m0 x7 h4 y2f ff7 fs2 fc3 sc0 ls2 ws0">在讨论<span class="_ _3"> </span><span class="ff4">RS-2<span class="ls3">3</span>2C<span class="_ _3"> </span><span class="ff2">接口</span></span>标准<span class="ff2">的</span><span class="ls3">内容<span class="ffa">之</span>前<span class="_ _0"></span><span class="ff2">，</span></span><span class="ffa">先说<span class="ff2">明</span><span class="ls3">两点<span class="_ _0"></span><span class="ff2">：<span class="ff4"> <span class="fc0"> </span></span></span></span></span></div><div class="t m0 x7 h4 y30 ffa fs2 fc3 sc0 ls2 ws0">首先<span class="ff2">，<span class="_ _9"></span><span class="ff4">RS-232-C<span class="_ _a"></span><span class="ff7">标准<span class="ffa">最初</span>是<span class="ffa ls3">远程</span><span class="ff2">通信<span class="ffa">连</span>接</span>数据<span class="ffa">终<span class="_ _5"></span><span class="ff7">端<span class="ls3">设备<span class="_ _b"> </span></span><span class="ff4">DTE(Dat<span class="ls3">a<span class="ls10"> </span></span>Termin<span class="ls3">a</span>l<span class="ls10"> </span>Equip<span class="ls3">m</span>ent)</span></span></span></span></span></span></div><div class="t m0 x1 h4 y31 ff2 fs2 fc3 sc0 ls2 ws0">与<span class="ff7">数据</span>通信<span class="ff7">设备<span class="_ _4"> </span><span class="ff4">DCE<span class="ffa">（</span>Data C<span class="ls3">o</span>mmunica<span class="ls3">t</span>ion Equ<span class="ls3">i</span>pme<span class="ls3">n</span>t)</span>而</span>制<span class="ff7">定</span>的<span class="ff7">。<span class="ffa">因此</span><span class="ls3">这</span>个标准</span><span class="ls3">的制<span class="ff7">定</span>，</span></div><div class="t m0 x1 h7 y32 ffa fs2 fc3 sc0 ls2 ws0">并未考虑<span class="ff7">计</span>算<span class="ff2">机</span>系统<span class="_ _5"></span><span class="ff2">的<span class="ff7">应用<span class="ffa ls3">要求</span><span class="ls14">。</span>但目前它<span class="ffa">又广泛<span class="ls3">地</span>被借</span></span>来<span class="ff7">用<span class="ls3">于计<span class="ffa">算<span class="_ _0"></span><span class="ff2">机<span class="_ _8"></span><span class="ffa ls2">（更<span class="ff7 ls3">准确<span class="_ _0"></span><span class="ff2">的<span class="ffa">说<span class="_ _0"></span></span>，<span class="_ _c"></span><span class="ff7 ls2">是计</span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h7 y33 ffa fs2 fc3 sc0 ls2 ws0">算<span class="ff2">机接口<span class="ff7">）<span class="_ _8"></span><span class="ff2">与<span class="ffa">终<span class="ff7">端</span>或外<span class="ff7">设<span class="_ _5"></span><span class="ffa">之间<span class="ff2">的</span>近<span class="_ _5"></span><span class="ff7">端<span class="ffa">连<span class="ff2">接</span></span><span class="ls3">标</span>准。<span class="_ _8"></span><span class="ffa">显然<span class="_ _5"></span><span class="ff2">，<span class="_ _8"></span><span class="ff7">这个标准<span class="ff2">的有<span class="_ _5"></span><span class="ffa">些<span class="ff2">规<span class="ff7">定</span><span class="ls3">及和<span class="ff7">计<span class="_ _0"></span><span class="ffa">算<span class="_ _0"></span></span></span>机</span></span>系统</span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y34 ff7 fs2 fc3 sc0 ls2 ws0">是<span class="ff2">不</span>一<span class="ffa">致<span class="ff2">的，<span class="_ _8"></span><span class="ffa ls3">甚至<span class="ff7">是<span class="_ _0"></span></span><span class="ls2">相</span>矛盾<span class="_ _0"></span><span class="ff2">的<span class="ff7">。<span class="_ _c"></span><span class="ff2">有<span class="_ _0"></span><span class="ff7 ls2">了<span class="ls3">对</span>这种<span class="ffa">背景<span class="_ _5"></span><span class="ff2">的<span class="ff7">了</span>解<span class="ls14">，我<span class="_ _a"> </span><span class="ffa">们<span class="_ _4"> </span><span class="ff7">对<span class="_ _d"> </span></span></span></span><span class="ff4">RS-<span class="ls3">2</span>32C<span class="_ _3"> </span><span class="ff7">标准</span></span>与<span class="ff7">计<span class="ffa">算</span></span><span class="ls3">机不<span class="ff7">兼</span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y35 ff7 fs2 fc3 sc0 ls3 ws0">容<span class="ff2">的<span class="_ _0"></span><span class="ffa">地<span class="_ _0"></span></span>方<span class="ffa">就</span>不<span class="_ _0"></span><span class="ffa">难</span><span class="ls2">理解<span class="ff7">了。<span class="ff4"> <span class="fc0"> </span></span></span></span></span></div><div class="t m0 x7 h4 y36 ffa fs2 fc3 sc0 ls2 ws0">其次<span class="ff2">，<span class="_ _8"></span><span class="ff4">RS-2<span class="ls3">3</span>2C<span class="_ _3"> </span><span class="ff7">标准<span class="ffa">中<span class="ff2">所</span>提到<span class="_ _5"></span><span class="ff2">的<span class="ffa">“</span>发<span class="ffa ls3">送”<span class="ff2">和<span class="_ _0"></span></span>“<span class="ff2">接收<span class="_ _0"></span></span>”<span class="ff2">，<span class="_ _8"></span><span class="ff7 ls2">都是<span class="ffa">站</span>在<span class="_ _3"> </span><span class="ff4">DTE<span class="_ _3"> </span><span class="ffa">立场<span class="_ _5"></span><span class="ff7">上<span class="ff2">，<span class="_ _8"></span><span class="ff7">而<span class="ff2">不</span>是<span class="ffa">站</span></span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y37 ff7 fs2 fc3 sc0 ls2 ws0">在<span class="_ _3"> </span><span class="ff4">DCE<span class="_ _3"> </span><span class="ff2">的<span class="ffa ls3">立场<span class="ff2">来<span class="_ _0"></span></span></span></span></span>定义<span class="ff2">的</span><span class="ls14">。</span>由于在计<span class="_ _5"></span><span class="ffa">算<span class="ff2">机</span>系<span class="ls3">统中<span class="ff2">，<span class="_ _c"></span><span class="ffa ls2">往往<span class="ff7">是<span class="_ _3"> </span><span class="ff4">CPU<span class="_ _3"> </span><span class="ff2">和<span class="_ _3"> </span></span>I<span class="ls3">/O<span class="_ _3"> </span></span></span>设备</span><span class="ls3">之间<span class="_ _0"></span><span class="ff7">传</span>送<span class="_ _0"></span><span class="ff2">信</span>息<span class="ff2">，<span class="_ _c"></span><span class="ffa">两<span class="_ _0"></span><span class="ff2">者</span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y38 ff7 fs2 fc3 sc0 ls2 ws0">都是<span class="_ _3"> </span><span class="ff4">DTE<span class="ff2">，<span class="ffa ls3">因此</span>双方</span></span>都能<span class="ff2">发<span class="ffa">送</span>和接收</span>。<span class="ff4"> <span class="fc0"> </span></span></div><div class="t m0 x7 h4 y39 ffb fs2 fc3 sc3 ls2 ws0">一、<span class="ff8 sc0">RS-232-C<span class="ff4"> <span class="fc0"> </span></span></span></div><div class="t m0 x7 h4 y3a ff4 fs2 fc3 sc0 ls2 ws0">RS-232C<span class="_ _3"> </span><span class="ff7">标准<span class="ffa">（<span class="ff2">协议<span class="_ _5"></span><span class="ff7">）<span class="ff2">的全<span class="ffa">称<span class="_ _5"></span><span class="ff7">是<span class="_ _3"> </span><span class="ff4">EIA-RS-<span class="_ _5"></span>232C<span class="_ _3"> </span><span class="ff7 ls3">标准<span class="ff2">，</span></span><span class="ffa">其中<span class="_ _3"> </span></span>EIA(El<span class="ls3">e</span>ctroni<span class="ls3">c</span> Indust<span class="ls3">r</span>y </span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y3b ff4 fs2 fc3 sc0 ls2 ws0">Associatio<span class="ls3">n)</span><span class="ffa">代表<span class="ff7 ls3">美国<span class="_ _0"></span><span class="ff2">电<span class="_ _0"></span></span>子<span class="ff2">工</span>业<span class="_ _0"></span><span class="ff2">协</span>会<span class="_ _0"></span><span class="ff2">，<span class="_ _0"></span><span class="ff4">RS<span class="ffa">（<span class="_ _0"></span></span></span></span></span></span>eco<span class="ls3">m</span>med<span class="ls3">e</span>d<span class="ls15"> </span>standard<span class="ff7">）<span class="ffa ls3">代<span class="ls2">表推荐</span><span class="ff7">标准<span class="ff2">，<span class="_ _0"></span></span></span></span></span>232<span class="_ _3"> </span><span class="ff7">是标</span></div><div class="t m0 x1 h4 y3c ff2 fs2 fc3 sc0 ls2 ws0">识<span class="ff7">号</span>，<span class="_ _5"></span><span class="ff4">C<span class="_ _4"></span><span class="ffa">代表<span class="_ _3"> </span></span>RS<span class="ls3">2</span>32<span class="_ _3"> </span><span class="ff2">的<span class="ffa">最新<span class="ff7">一</span>次修<span class="ff7">改<span class="_ _7"></span><span class="ffa">（<span class="ff4">1<span class="ls3">9</span>69<span class="ff7">）<span class="_ _e"></span><span class="ff2">，<span class="_ _e"></span><span class="ff7 ls3">在这<span class="ffa">之<span class="_ _0"></span></span>前<span class="ff2 ls16">，有<span class="_ _f"> </span><span class="ff4 ls2">RS232B<span class="ff7">、<span class="_ _e"></span><span class="ff4">RS<span class="ls3">2</span>32A<span class="ff7 ls16">。<span class="ls17">。它<span class="ff2">规<span class="_ _0"></span></span>定<span class="_ _0"></span><span class="ffa">连</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y3d ff2 fs2 fc3 sc0 ls2 ws0">接电<span class="ffa">缆</span>和机<span class="ffa">械<span class="ff7">、</span></span>电<span class="ffa">气<span class="_ _e"></span><span class="ff7">特性、<span class="ff2">信</span>号功能<span class="ff2">及<span class="_ _e"></span><span class="ff7">传<span class="ffa">送</span>过<span class="ffa">程</span>。<span class="ffa">常<span class="_ _5"></span><span class="ff7">用<span class="ffa">物<span class="ff2">理</span></span>标准<span class="ffa">还<span class="ff2">有有<span class="_ _4"> </span><span class="ff4">E<span class="ls3">I</span>A&#0;RS-232-C</span></span></span>、</span></span></span></span></span></span></div><div class="t m0 x1 h4 y3e ff4 fs2 fc3 sc0 ls2 ws0">EIA&#0;RS-<span class="ls3">4</span>22-A<span class="ff7">、</span>E<span class="ls3">I</span>A&#0;RS-423A<span class="ff7">、</span>E<span class="ls3">I</span>A&#0;RS<span class="_ _e"></span>-485<span class="ff7">。</span> <span class="ff7">这<span class="ffa">里<span class="ff2">只</span><span class="ls3">介绍<span class="_ _3"> </span></span></span></span>EIA&<span class="ls3">#</span>0;RS-232-C<span class="ffa">（简</span></div><div class="t m0 x1 h4 y3f ffa fs2 fc3 sc0 ls2 ws0">称<span class="_ _3"> </span><span class="ff4">232<span class="ff2">，</span>RS2<span class="ls3">32</span><span class="ff7">）。</span> </span>例<span class="ff7">如<span class="ff2">，</span><span class="ls3">目</span>前在<span class="_ _3"> </span><span class="ff4">IBM <span class="ls3">PC<span class="_ _3"> </span><span class="ff2">机<span class="_ _0"></span><span class="ff7">上</span>的<span class="_ _6"> </span></span></span>CO<span class="ls3">M1<span class="ff7">、<span class="_ _0"></span></span></span>COM2<span class="_ _3"> </span><span class="ff2">接<span class="ls3">口，<span class="ffa">就<span class="_ _0"></span><span class="ff7">是<span class="_ _6"> </span><span class="ff4">RS-<span class="_ _0"></span></span></span></span></span></span>232C<span class="_ _4"> </span><span class="ff2">接口</span></span>。<span class="ff4"> <span class="fc0"> </span></span></span></div><div class="t m0 x7 h4 y40 ff4 fs2 fc3 sc0 ls2 ws0">1.<span class="ff2">电<span class="ffa">气<span class="ff7">特性</span></span></span> <span class="fc0"> </span></div><div class="t m0 x7 h4 y41 ff4 fs2 fc3 sc0 ls2 ws0">EIA-RS-232C<span class="_ _4"> </span><span class="ff7">对<span class="ff2">电</span><span class="ls3">器</span>特性、<span class="ffa ls3">逻辑<span class="_ _0"></span><span class="ff2">电<span class="_ _0"></span></span>平<span class="ff2">和</span>各<span class="_ _0"></span><span class="ff7">种<span class="ff2">信<span class="_ _0"></span></span>号<span class="ff2">线<span class="_ _0"></span></span>功</span></span>能都<span class="ff2">作</span>了<span class="ff2">规<span class="_ _e"></span><span class="ff7">定。<span class="ff4"> <span class="fc0"> </span></span></span></span></span></div><div class="t m0 x8 h4 y42 ff7 fs2 fc3 sc0 ls2 ws0">在<span class="_ _3"> </span><span class="ff4">TxD<span class="_ _3"> </span><span class="ff2">和<span class="_ _3"> </span></span>R<span class="ls3">xD<span class="_ _3"> </span><span class="ff7">上<span class="_ _0"></span><span class="ff2">：<span class="_ _0"></span><span class="ffa">逻辑<span class="_ _3"> </span></span></span></span></span>1(MAR<span class="ls3">K</span>)=-3V</span>～<span class="ff4">-15V <span class="fc0"> </span></span></div><div class="t m0 x8 h4 y43 ff4 fs2 fc3 sc0 ls2 ws0"> <span class="ls3"> </span> <span class="ffa ls3">逻辑<span class="_ _6"> </span></span>0(SPA<span class="ls3">C</span>E)=+3<span class="ff7">～<span class="ffa">＋</span></span>15V <span class="fc0"> </span></div><div class="t m0 x8 h4 y44 ff7 fs2 fc3 sc0 ls2 ws0">在<span class="_ _3"> </span><span class="ff4">RTS</span>、<span class="ff4">CTS</span>、<span class="ff4">DSR</span>、<span class="ff4 ls3">D<span class="ls2">TR<span class="_ _4"> </span><span class="ff2">和<span class="_ _3"> </span></span>DCD<span class="_ _3"> </span></span></span>等<span class="ff2">控制线</span>上<span class="ff2">：<span class="ff4"> <span class="fc0"> </span></span></span></div><div class="t m0 x8 h4 y45 ff2 fs2 fc3 sc0 ls2 ws0">信<span class="ff7">号</span>有<span class="ffa">效（</span>接通，<span class="ff4">ON<span class="_ _4"></span><span class="ffa">状态</span></span>，<span class="ffa">正</span>电<span class="ffa">压<span class="ff7">）</span>＝<span class="_ _e"></span><span class="ff4">+3V<span class="ff7">～</span>+1<span class="ls3">5</span>V <span class="fc0"> </span></span></span></div><div class="t m0 x8 h4 y46 ff2 fs2 fc3 sc0 ls2 ws0">信<span class="ff7">号<span class="ffa">无效<span class="ls3">（断</span></span></span>开，<span class="ff4">O<span class="ls3">FF<span class="_ _6"> </span></span><span class="ffa">状态</span></span><span class="ls3">，</span>负电<span class="ffa">压<span class="ff4">)=-3V<span class="ff7">～</span>-15<span class="ls3">V <span class="fc0"> </span></span></span></span></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.613445,0.000000,0.000000,1.613445,0.000000,0.000000]}'></div></div>
<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62501a1374bc5c01055afd88/bg3.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">R<span class="ls1">S<span class="ls2">232<span class="_"> </span><span class="ff2 ls3">技<span class="ls2">术</span>文摘</span><span class="ls4"> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ff2 ls3">枕<span class="ls2">善</span>居<span class="ls2">收</span>集<span class="ls2">整理</span></span><span class="ls5"> </span> <span class="ls5"> </span> <span class="ls3">h<span class="ls6">t<span class="ls7">t</span></span></span></span>p<span class="ls8">:<span class="ls6">//<span class="ls9">ww<span class="lsa">w<span class="lsb">.<span class="ls7">m<span class="ls3">n</span></span></span></span></span></span></span>d<span class="lsc">s<span class="ls3">o<span class="lsd">f<span class="ls6">t.<span class="lse">c</span></span></span>om </span></span></span></span></div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 lsd ws0">-<span class="lsb"> <span class="ls2">3</span> </span>- </div><div class="t m0 x9 h4 y47 ff4 fs2 fc0 sc0 lsd ws0"> </div><div class="t m0 xa h4 y48 ffa fs2 fc3 sc0 lsd ws0">图<span class="_ _3"> </span><span class="ff4 ls2">1 <span class="fc0"> </span></span></div><div class="t m0 x7 h4 yf ff7 fs2 fc3 sc0 ls2 ws0">以上<span class="ff2">规</span>定<span class="ffa">说<span class="ff2">明</span></span>了<span class="_ _4"> </span><span class="ff4">RS-<span class="ls3">3</span>23C<span class="_ _3"> </span></span>标<span class="ls3">准对<span class="_ _0"></span></span><span class="ffa">逻辑<span class="ff2">电</span>平<span class="ff2">的</span></span>定义<span class="ls18">。<span class="ls3">对</span></span>于数据<span class="_ _1"></span><span class="ffa">（<span class="ff2">信</span><span class="ls3">息码<span class="ff7">）<span class="_ _10"></span><span class="ff2">：<span class="_ _1"></span><span class="ffa ls2">逻辑“<span class="ff4">1</span><span class="ls10">”（<span class="_ _3"> </span><span class="ff7">传</span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y10 ff7 fs2 fc3 sc0 ls2 ws0">号）<span class="ff2">的电<span class="ffa">平<span class="ffc">低</span></span></span>于<span class="ff4">-3V<span class="ff2">，<span class="_ _e"></span><span class="ffa">逻辑“<span class="ff4">0</span>”（<span class="ffc">空<span class="ff7 ls3">号）</span><span class="ff2">的电</span></span>平<span class="ffc">告语<span class="_ _e"></span><span class="ff4">+3V<span class="ffc">；<span class="ff7">对于<span class="ff2 ls3">控<span class="ls2">制信</span></span>号</span>；<span class="ff2">接通<span class="ffa">状<span class="ls3">态（</span></span></span></span>ON<span class="ff7">）</span></span></span></span></span></span></div><div class="t m0 x1 h4 y11 ffc fs2 fc3 sc0 ls2 ws0">即<span class="ff2">信<span class="ff7">号</span>有<span class="ffa">效</span>的电<span class="ffa">平</span></span>高<span class="_ _e"></span><span class="ff7">于<span class="ff4">+3V<span class="ff2">，<span class="ffa">断</span>开<span class="ffa">状态</span></span>(<span class="ls3">O</span>FF)<span class="ffc">即<span class="ff2">信<span class="_ _e"></span><span class="ff7">号<span class="ffa ls3">无效<span class="_ _0"></span></span><span class="ff2">的电<span class="ffa">平<span class="ffc">低</span></span></span>于<span class="ff4">-3V<span class="ff2">，<span class="ffc">也<span class="_ _e"></span><span class="ffa">就<span class="ff7">是<span class="ffc">当</span><span class="ls3">传输<span class="_ _0"></span><span class="ff2">电<span class="ffa">平</span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y12 ff2 fs2 fc3 sc0 ls3 ws0">的<span class="ffc">绝<span class="_ _0"></span><span class="ff7">对<span class="_ _0"></span></span><span class="ls2">值大<span class="_ _e"></span><span class="ff7">于<span class="_ _3"> </span><span class="ff4">3V<span class="_ _3"> </span><span class="ffc">时<span class="ff2 ls19">，<span class="ls2">电路</span></span>可</span></span>以<span class="ff2">有<span class="ffa">效地<span class="_ _e"></span><span class="ff7">检<span class="ffc">查出<span class="ff2 ls3">来，<span class="_ _10"></span><span class="ffa">介<span class="_ _0"></span><span class="ff7">于<span class="ff4 ls2">-3<span class="ff7">～</span>+3V<span class="_ _3"> </span><span class="ffa">之间<span class="ff2">的电</span></span></span></span>压无<span class="ffc">意<span class="_ _0"></span><span class="ff7">义<span class="ff2">，<span class="_ _10"></span><span class="ffc">低<span class="_ _0"></span><span class="ff7">于<span class="ff4">-<span class="_ _0"></span><span class="ls2">15V</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y13 ffa fs2 fc3 sc0 ls2 ws0">或<span class="ffc">高<span class="ff7">于<span class="ff4">+15V<span class="_ _4"> </span><span class="ff2">的电</span></span></span></span>压<span class="ffc ls3">也认<span class="_ _0"></span><span class="ff2">为<span class="_ _0"></span><span class="ffa">无</span></span>意<span class="ff7">义<span class="_ _0"></span><span class="ff2">，</span></span></span>因此<span class="ff2">，实<span class="ffc">际</span><span class="ls3">工作<span class="ffc">时</span>，<span class="_ _0"></span><span class="ff7">应<span class="_ _0"></span></span></span><span class="ffc">保证</span>电<span class="_ _e"></span><span class="ffa">平<span class="ff7">在<span class="ffc">±<span class="ff4">(3</span></span>～<span class="ff4">15)V<span class="_ _3"> </span></span></span><span class="ls3">之间<span class="ff7">。<span class="_ _0"></span><span class="ff4"> <span class="_ _0"></span><span class="fc0"> </span></span></span></span></span></span></div><div class="t m0 x7 h4 y49 ff4 fs2 fc3 sc0 ls2 ws0">EIA-RS-232C<span class="_ _4"> </span><span class="ff2">与<span class="_ _3"> </span></span>TTL<span class="_ _3"> </span><span class="ffc">转换<span class="ff2">：<span class="_ _c"></span><span class="ff4">E<span class="ls3">IA<span class="_ _0"></span>-<span class="_ _0"></span></span>RS-23<span class="ls3">2C<span class="_ _3"> </span></span><span class="ff7">是用<span class="ffa">正<span class="ff2">负电</span>压<span class="_ _e"></span><span class="ff2">来<span class="ffa">表<span class="ffc">示</span>逻<span class="ls3">辑</span>状态</span><span class="ls13">，与<span class="_ _11"> </span></span><span class="ff4">TTL<span class="_ _3"> </span><span class="ff7">以<span class="ffc ls3">高低</span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y4a ff2 fs2 fc3 sc0 ls3 ws0">电<span class="ffa ls2">平表<span class="ffc">示</span><span class="ls3">逻</span>辑状态</span>的规<span class="_ _0"></span><span class="ff7">定<span class="_ _0"></span></span><span class="ls2">不同<span class="ff7">。<span class="_ _8"></span><span class="ffa ls3">因此<span class="ff2 ls14">，为<span class="_ _12"> </span><span class="ff7 ls2">了能<span class="ffc">够<span class="ff2">同</span></span>计<span class="_ _e"></span><span class="ffa">算<span class="ff2">机接口</span><span class="ls3">或终<span class="_ _0"></span><span class="ff7">端<span class="ff2">的<span class="_ _6"> </span></span></span></span><span class="ff4">T<span class="ls3">TL<span class="_ _6"> </span><span class="ff7">器<span class="ff2">件<span class="_ _0"></span><span class="ffa">连</span><span class="ls2">接，<span class="_ _8"></span><span class="ffc">必须</span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y4b ff7 fs2 fc3 sc0 ls2 ws0">在<span class="_ _3"> </span><span class="ff4">EIA-RS-2<span class="ls3">3</span>2C<span class="_ _3"> </span><span class="ff2">与<span class="_ _3"> </span></span>T<span class="ls3">TL<span class="_ _3"> </span></span><span class="ff2">电路<span class="ffa ls3">之间<span class="_ _0"></span><span class="ff7">进<span class="_ _0"></span></span></span>行电<span class="_ _e"></span><span class="ffa">平<span class="ff2">和</span>逻辑<span class="ff2">关</span>系<span class="ff2">的<span class="ffc">变换<span class="ff7">。<span class="_ _9"></span><span class="ff2">实<span class="ffc">现<span class="ff7 ls3">这种<span class="_ _0"></span></span>变换</span><span class="ls3">的</span>方法<span class="ffc">可<span class="ff7">用</span>分<span class="ffa">立</span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y4c ffc fs2 fc3 sc0 ls2 ws0">元<span class="ff2">件，<span class="_ _e"></span><span class="ffc">也可<span class="ff7">用<span class="ff2">集</span>成<span class="ff2 ls3">电路<span class="ffc">芯<span class="_ _0"></span><span class="ff7">片<span class="ls17">。</span></span></span></span>目前</span>较<span class="_ _e"></span><span class="ff2">为<span class="ffa">广泛地<span class="ff7">使用</span></span>集<span class="ff7">成</span>电路<span class="ffc">转换<span class="_ _e"></span><span class="ff7">器<span class="ff2">件，<span class="_ _e"></span><span class="ff7">如<span class="_ _3"> </span><span class="ff4">MC1488<span class="_ _5"></span><span class="ff7">、<span class="_ _e"></span><span class="ff4">SN751<span class="ls3">50</span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y4d ffc fs2 fc3 sc0 ls3 ws0">芯<span class="ff7">片<span class="_ _0"></span></span><span class="ls2">可完<span class="ff7">成<span class="_ _3"> </span></span></span><span class="ff4">T<span class="ls2">TL<span class="_ _3"> </span><span class="ff2">电</span></span><span class="ffa">平到<span class="_ _6"> </span></span><span class="ls2">EIA<span class="_ _3"> </span><span class="ff2">电<span class="_ _5"></span><span class="ffa">平<span class="ff2">的<span class="ffc">转换</span>，<span class="_ _1"></span><span class="ff7">而<span class="_ _3"> </span><span class="ff4">MC14<span class="ls3">89<span class="ff7">、<span class="_ _13"></span><span class="ff4">S<span class="ls2">N75154<span class="_ _3"> </span><span class="ffc">可<span class="ff2">实</span>现<span class="_ _4"> </span></span>EIA<span class="_ _3"> </span><span class="ff2">电<span class="ffa">平到<span class="_ _3"> </span></span></span>TTL<span class="_ _4"> </span><span class="ff2">电<span class="ffa">平</span>的</span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y4e ffc fs2 fc3 sc0 ls2 ws0">转换<span class="ff7">。<span class="_ _7"></span><span class="ff4">MA<span class="ls3">X</span>232<span class="_ _3"> </span><span class="ffc">芯<span class="ff7">片</span>可完<span class="ff7">成<span class="_ _3"> </span></span></span><span class="ls3">T</span>TL<span class="ffc">←→</span>E<span class="ls3">IA<span class="_ _3"> </span><span class="ff2">双<span class="_ _0"></span><span class="ffc">向</span>电<span class="ffa">平<span class="_ _0"></span></span></span></span><span class="ffc">转换<span class="ff2">，<span class="_ _c"></span><span class="ffa">图<span class="_ _3"> </span><span class="ff4">1<span class="_ _3"> </span></span>显<span class="ffc">示<span class="ff7">了<span class="_ _3"> </span><span class="ff4">14<span class="ls3">88<span class="_ _3"> </span><span class="ff2">和<span class="_ _6"> </span></span></span>1489<span class="_ _3"> </span><span class="ff2">的</span></span>内</span>部<span class="ls3">结构</span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y4f ff2 fs2 fc3 sc0 ls3 ws0">和<span class="ffc ls2">引脚<span class="ff7">。</span></span><span class="ff4">M<span class="ls2">C1488<span class="_ _3"> </span><span class="ff2">的<span class="ffc">引脚</span></span>(2)<span class="_ _e"></span><span class="ff7">、<span class="ff4">(4,5)<span class="_ _e"></span><span class="ff7">、<span class="ff4">(9,<span class="ls3">1</span>0)<span class="ff2">和</span>(12<span class="ls3">,</span>1<span class="ls3">3)<span class="ff2">接<span class="_ _6"> </span></span></span>TTL<span class="_ _3"> </span></span>输<span class="ffc">入</span>。<span class="_ _e"></span><span class="ffc">引脚<span class="_ _3"> </span><span class="ff4">3<span class="ff7">、<span class="_ _e"></span><span class="ff4">6<span class="ff7">、<span class="_ _5"></span><span class="ff4">8<span class="ff7">、</span><span class="ls3">11<span class="_ _3"> </span><span class="ff7">输<span class="_ _0"></span><span class="ffc">出</span></span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y50 ff7 fs2 fc3 sc0 ls3 ws0">端<span class="ff2">接<span class="_ _6"> </span><span class="ff4 ls2">EIA-RS-232C<span class="ff7">。<span class="_ _e"></span><span class="ff4 ls3">M<span class="ls2">C1498<span class="_ _3"> </span><span class="ff2">的<span class="_ _3"> </span></span>14<span class="_ _3"> </span><span class="ff2">的<span class="_ _3"> </span></span>1<span class="_ _5"></span><span class="ff7">、<span class="ff4">4</span>、<span class="_ _e"></span><span class="ff4">10<span class="ff7">、<span class="_ _e"></span><span class="ff4">13<span class="_ _3"> </span><span class="ffc">脚<span class="ff2">接<span class="_ _3"> </span></span></span>EIA<span class="_ _3"> </span><span class="ff7">输<span class="ffc">入<span class="_ _5"></span><span class="ff2">，<span class="ff7">而<span class="_ _4"> </span><span class="ff4">3</span>、<span class="ff4">6</span>、<span class="_ _e"></span><span class="ff4">8<span class="ff7">、</span><span class="ls3">11<span class="_ _3"> </span><span class="ffc">脚<span class="_ _0"></span><span class="ff2">接<span class="_ _3"> </span></span></span></span>T<span class="ls3">TL</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y51 ff7 fs2 fc3 sc0 ls3 ws0">输<span class="ffc">出<span class="_ _0"></span></span>。<span class="_ _0"></span><span class="ffc ls2">具体<span class="_ _e"></span><span class="ffa">连<span class="ff2">接方法<span class="ff7">如</span></span>图<span class="_ _3"> </span><span class="ff4">2<span class="_ _3"> </span><span class="ff2">所<span class="ffc">示<span class="ff7">。</span></span></span></span>图中<span class="_ _e"></span><span class="ff2">的<span class="ffc">左边<span class="ff7">是<span class="ffa">微</span></span></span><span class="ls3">机</span>串行接口<span class="ls3">电路<span class="ffa">中<span class="_ _0"></span></span>的<span class="ff7">主<span class="ffc">芯<span class="_ _0"></span></span>片<span class="_ _3"> </span></span></span><span class="ff4">UART</span>，<span class="ff7">它是</span></span></span></span></div><div class="t m0 x1 h4 y52 ff4 fs2 fc3 sc0 ls2 ws0">TTL<span class="_ _3"> </span><span class="ff7">器<span class="ff2">件，<span class="ffc ls3">右边<span class="ff7">是<span class="_ _6"> </span></span></span></span></span>EIA-RS-23<span class="ls3">2C<span class="_ _3"> </span><span class="ffa">连<span class="_ _0"></span><span class="ff2">接<span class="ff7">器</span>，<span class="_ _0"></span></span><span class="ls2">要求<span class="_ _3"> </span></span></span></span>E<span class="ls3">IA<span class="_ _3"> </span><span class="ffc">高<span class="ff2">电<span class="_ _0"></span><span class="ffa">压<span class="_ _0"></span><span class="ff7">。</span><span class="ls2">因此<span class="ff2">，</span></span></span></span></span></span>RS-23<span class="ls3">2C<span class="_ _3"> </span></span><span class="ff2">所有的<span class="ff7">输<span class="ffc">出</span>、输</span></span></div><div class="t m0 x1 h4 y53 ffc fs2 fc3 sc0 ls2 ws0">入<span class="ff2">信<span class="ff7">号都<span class="ffa">要</span></span></span>分别<span class="ff7">经过<span class="_ _4"> </span><span class="ff4">MC1488<span class="_ _4"> </span><span class="ff2">和<span class="_ _3"> </span></span>MC1498<span class="_ _3"> </span></span></span>转换<span class="ff7">器<span class="ff2">，<span class="_ _14"></span><span class="ff7">进<span class="ff2 ls3">行电<span class="ffa">平<span class="_ _0"></span></span></span><span class="ffc">转换<span class="ls3">后才<span class="_ _0"></span><span class="ff7">能</span></span><span class="ffa">送<span class="ls3">到连<span class="_ _0"></span><span class="ff2">接</span></span></span></span>器上<span class="ffc">去<span class="ffa">或</span></span>从<span class="ffa">连</span></span></span></span></div><div class="t m0 x1 h4 y54 ff2 fs2 fc3 sc0 ls2 ws0">接<span class="ff7">器上<span class="ffa">送</span>进</span>来<span class="ff7">。<span class="ff4"> <span class="fc0"> </span></span></span></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.613445,0.000000,0.000000,1.613445,0.000000,0.000000]}'></div></div>
<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62501a1374bc5c01055afd88/bg4.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">R<span class="ls1">S<span class="ls2">232<span class="_"> </span><span class="ff2 ls3">技<span class="ls2">术</span>文摘</span><span class="ls4"> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ff2 ls3">枕<span class="ls2">善</span>居<span class="ls2">收</span>集<span class="ls2">整理</span></span><span class="ls5"> </span> <span class="ls5"> </span> <span class="ls3">h<span class="ls6">t<span class="ls7">t</span></span></span></span>p<span class="ls8">:<span class="ls6">//<span class="ls9">ww<span class="lsa">w<span class="lsb">.<span class="ls7">m<span class="ls3">n</span></span></span></span></span></span></span>d<span class="lsc">s<span class="ls3">o<span class="lsd">f<span class="ls6">t.<span class="lse">c</span></span></span>om </span></span></span></span></div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 lsd ws0">-<span class="lsb"> <span class="ls2">4</span> </span>- </div><div class="t m0 xb h4 y55 ff4 fs2 fc0 sc0 lsd ws0"> </div><div class="t m0 xa h4 y56 ffa fs2 fc3 sc0 lsd ws0">图<span class="_ _3"> </span><span class="ff4 ls2">2 <span class="fc0"> </span></span></div><div class="t m0 x7 h4 y11 ff4 fs2 fc3 sc0 ls2 ws0">2<span class="ff7">、、<span class="ffa">连<span class="ff2">接</span></span>器<span class="ff2">的机<span class="ffa">械</span></span><span class="ls3">特性<span class="ff2">：<span class="ff4"> <span class="_ _0"></span><span class="fc0"> </span></span></span></span></span></div><div class="t m0 x7 h4 y57 ffa fs2 fc3 sc0 ls3 ws0">连<span class="ff2">接<span class="_ _0"></span><span class="ff7">器<span class="_ _0"></span></span>：<span class="_ _15"></span><span class="ff7 ls2">由于<span class="_ _3"> </span><span class="ff4">RS-2<span class="ls3">3</span>2C<span class="_ _3"> </span><span class="ffa">并未</span></span>定义<span class="ffa">连<span class="ff2">接<span class="_ _e"></span><span class="ff7">器<span class="ff2">的<span class="ffa">物</span>理</span>特性<span class="ff2">，<span class="_ _16"></span><span class="ffa ls3">因此<span class="ff2">，<span class="_ _17"></span><span class="ffc ls2">出现<span class="ff7">了<span class="_ _4"> </span><span class="ff4">DB-25</span>、<span class="_ _15"></span><span class="ff4">DB-15<span class="_ _3"> </span><span class="ff2">和<span class="_ _3"> </span></span>DB-9</span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y58 ffa fs2 fc3 sc0 ls2 ws0">各<span class="ff7">种<span class="ffc">类型<span class="ff2">的</span></span></span>连<span class="ff2">接<span class="ff7">器</span>，<span class="_ _e"></span><span class="ffa">其<span class="ffc">引脚<span class="ff2">的<span class="ff7">定义</span></span>也</span>各<span class="_ _e"></span><span class="ff2">不<span class="ffa">相</span>同<span class="ff7">。<span class="ffc">下<span class="ls3">面</span>分别<span class="ffa">介绍两<span class="_ _5"></span><span class="ff7">种<span class="ffa">连<span class="ff2">接</span></span><span class="ls3">器。<span class="ff4"> <span class="_ _0"></span><span class="fc0"> </span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x7 h4 y59 ffa fs2 fc3 sc0 ls3 ws0">（<span class="ff4">1<span class="_ _0"></span><span class="ff7">）<span class="_ _e"></span><span class="ff4 ls2">DB-25<span class="ff2">：<span class="_ _e"></span><span class="ff4"> PC<span class="_ _3"> </span><span class="ff2">和<span class="_ _4"> </span></span>XT<span class="_ _3"> </span><span class="ff2">机<span class="ff7 ls3">采用<span class="_ _6"> </span></span></span>DB-25<span class="_ _3"> </span><span class="ffc">型<span class="ffa">连<span class="ff2">接<span class="ff7">器。<span class="_ _7"></span><span class="ff4">DB-<span class="ls3">25<span class="_ _3"> </span><span class="ffa">连<span class="_ _0"></span><span class="ff2">接<span class="_ _0"></span></span></span></span><span class="ff7">器定<span class="ls3">义了<span class="_ _3"> </span></span></span>25<span class="_ _3"> </span><span class="ffc">根<span class="ff2">信<span class="ff7">号</span>线，<span class="_ _7"></span><span class="ffc">分</span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y5a ff2 fs2 fc3 sc0 ls2 ws0">为<span class="_ _3"> </span><span class="ff4">4<span class="_ _3"> </span><span class="ffc">组</span></span>：<span class="ff4"> <span class="fc0"> </span></span></div><div class="t m0 x8 h4 y5b ffc fs2 fc3 sc0 ls2 ws0">①异<span class="ff2">步通<span class="ls3">信的<span class="_ _3"> </span><span class="ff4">9<span class="_ _6"> </span><span class="ff7">个<span class="_ _0"></span></span></span>电<span class="ffa">压</span>信<span class="_ _0"></span><span class="ff7">号<span class="ffa">（<span class="ffc">含<span class="_ _0"></span></span></span></span>信<span class="_ _0"></span><span class="ff7">号<span class="ffa">地<span class="_ _3"> </span></span></span></span><span class="ff4">SG<span class="ff7">）</span>2</span>，<span class="ff4">3</span>，<span class="ff4">4<span class="_ _e"></span><span class="ff2">，<span class="ff4">5</span>，<span class="ff4">6</span>，<span class="ff4">7</span>，<span class="ff4">8</span>，<span class="ff4">20</span>，<span class="ff4 ls3">22 <span class="_ _0"></span><span class="fc0"> </span></span></span></span></span></div><div class="t m0 x8 h4 y5c ffc fs2 fc3 sc0 ls3 ws0">②<span class="ff4 ls2">20mA<span class="_ _3"> </span><span class="ff2">电流<span class="ffc">环</span>信<span class="ff7">号</span></span> 9<span class="_ _4"> </span><span class="ff7">个<span class="ffa">（</span></span>12<span class="ff2">，</span>13<span class="ff2">，</span>14<span class="ff2">，</span>15<span class="ff2">，</span>16<span class="_ _e"></span><span class="ff2">，<span class="ff4">17</span>，<span class="ff4">19,23</span>，<span class="ff4">24<span class="_ _e"></span><span class="ff7">）<span class="ff4"> <span class="fc0"> </span></span></span></span></span></span></div><div class="t m0 x8 h4 y5d ffc fs2 fc3 sc0 ls2 ws0">③空<span class="_ _3"> </span><span class="ff4">6<span class="_ _3"> </span><span class="ff7">个<span class="ffa">（</span></span>9<span class="ff2">，</span>10<span class="ff2">，</span>11<span class="_ _e"></span><span class="ff2">，<span class="ff4">18</span>，<span class="ff4">21</span>，<span class="ff4">25<span class="ff7">）</span> <span class="fc0"> </span></span></span></span></div><div class="t m0 x8 h4 y5e ffc fs2 fc3 sc0 ls2 ws0">④保护<span class="ffa">地（<span class="ff4 ls3">PE<span class="ff7">）<span class="_ _0"></span></span>1<span class="_ _6"> </span><span class="ff7">个</span></span><span class="ff2">，作为<span class="ff7 ls3">设备<span class="ff2">接<span class="_ _0"></span><span class="ffa">地</span></span>端<span class="ffa">（<span class="_ _0"></span><span class="ff4">1<span class="_ _6"> </span><span class="ffc">脚</span></span></span>）<span class="_ _0"></span><span class="ff4"> <span class="fc0"> </span></span></span></span></span></div><div class="t m0 x7 h4 y5f ff4 fs2 fc3 sc0 ls2 ws0">DB-25<span class="_ _3"> </span><span class="ffc">型<span class="ffa">连<span class="ff2">接<span class="ff7">器</span>的</span>外<span class="_ _e"></span><span class="ff7">形<span class="ff2">及信</span>号<span class="ff2">线<span class="ffc">分配</span></span>如<span class="_ _e"></span><span class="ffa">图<span class="_ _3"> </span><span class="ff4">3<span class="_ _3"> </span><span class="ff2">所<span class="ffc">示<span class="ff7">。</span><span class="ls3">注意<span class="ff2">，<span class="_ _0"></span></span></span></span></span>20mA<span class="_ _3"> </span><span class="ff2 ls3">电流<span class="ffc">环<span class="_ _0"></span></span>信<span class="_ _0"></span><span class="ff7">号<span class="ffc">仅<span class="_ _3"> </span></span></span></span>IBM<span class="ls10"> </span>PC<span class="_ _3"> </span><span class="ff2">和</span></span></span></span></span></span></div><div class="t m0 x1 h4 y60 ff4 fs2 fc3 sc0 ls2 ws0">IBM PC/XT<span class="_ _3"> </span><span class="ff2">机<span class="ffa">提<span class="ffc">供</span></span>，<span class="_ _e"></span><span class="ffa">至<span class="_ _3"> </span><span class="ff4">AT<span class="_ _3"> </span><span class="ff2">机及<span class="ff7">以<span class="ffc">后</span></span>，<span class="ff7">已<span class="_ _e"></span><span class="ff2">不<span class="ffc">支持<span class="ff7">。<span class="ff4"> <span class="fc0"> </span></span></span></span></span></span></span></span></span></span></div><div class="t m0 xc h4 y61 ff4 fs2 fc0 sc0 ls2 ws0"> </div><div class="t m0 xa h4 y62 ffa fs2 fc3 sc0 ls2 ws0">图<span class="_ _3"> </span><span class="ff4">3 <span class="fc0"> </span></span></div><div class="t m0 x7 h4 y63 ffa fs2 fc3 sc0 ls2 ws0">（<span class="ff4">2<span class="ff7">）</span>DB-9<span class="_ _3"> </span></span>连<span class="ff2">接<span class="ff7">器<span class="ff4"> <span class="fc0"> </span></span></span></span></div><div class="t m0 x7 h4 y64 ff7 fs2 fc3 sc0 ls2 ws0">在<span class="_ _3"> </span><span class="ff4">AT<span class="_ _3"> </span><span class="ff2">机及</span></span>以<span class="ffc">后<span class="ff2 ls1a">，不<span class="_ _18"></span></span>支持<span class="_ _3"> </span><span class="ff4">2<span class="ls3">0</span>mA<span class="_ _3"> </span><span class="ff2">电流</span></span>环<span class="ff2">接<span class="ls3">口，<span class="_ _e"></span><span class="ff7 ls2">使用<span class="_ _3"> </span><span class="ff4 ls3">DB<span class="ls2">-9<span class="_ _3"> </span><span class="ffa">连<span class="ff2">接</span></span></span></span>器<span class="ff2 ls1a">，<span class="ls2">作为<span class="ffa">提<span class="ffc ls3">供多</span></span></span></span>功能<span class="_ _3"> </span><span class="ff4 ls3">I<span class="ls2">/O<span class="_ _3"> </span><span class="ffc">卡</span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y65 ffa fs2 fc3 sc0 ls2 ws0">或<span class="ff7">主<span class="ffc">板</span>上<span class="_ _3"> </span><span class="ff4">CO<span class="ls3">M1<span class="_ _3"> </span><span class="ff2">和<span class="_ _6"> </span></span></span>CO<span class="ls3">M2<span class="_ _6"> </span><span class="ffa">两<span class="ff7">个<span class="_ _0"></span><span class="ff2">串<span class="ls2">行接口的</span></span></span></span></span></span></span>连<span class="ff2">接<span class="ff7 ls3">器<span class="ls1a">。它<span class="_ _18"></span><span class="ff2">只<span class="_ _18"></span><span class="ffa">提<span class="_ _a"></span></span></span></span></span><span class="ffc">供异</span>步<span class="ls3">通</span>信的<span class="_ _3"> </span><span class="ff4">9<span class="_ _3"> </span><span class="ff7">个<span class="_ _e"></span><span class="ff2">信<span class="ff7">号。<span class="_ _7"></span><span class="ff4">DB-25<span class="_ _3"> </span><span class="ffc">型<span class="_ _5"></span><span class="ffa">连</span></span></span></span></span></span></span></span></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.613445,0.000000,0.000000,1.613445,0.000000,0.000000]}'></div></div>
<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62501a1374bc5c01055afd88/bg5.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">R<span class="ls1">S<span class="ls2">232<span class="_"> </span><span class="ff2 ls3">技<span class="ls2">术</span>文摘</span><span class="ls4"> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ls5"> </span> <span class="ff2 ls3">枕<span class="ls2">善</span>居<span class="ls2">收</span>集<span class="ls2">整理</span></span><span class="ls5"> </span> <span class="ls5"> </span> <span class="ls3">h<span class="ls6">t<span class="ls7">t</span></span></span></span>p<span class="ls8">:<span class="ls6">//<span class="ls9">ww<span class="lsa">w<span class="lsb">.<span class="ls7">m<span class="ls3">n</span></span></span></span></span></span></span>d<span class="lsc">s<span class="ls3">o<span class="lsd">f<span class="ls6">t.<span class="lse">c</span></span></span>om </span></span></span></span></div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 lsd ws0">-<span class="lsb"> <span class="ls2">5</span> </span>- </div><div class="t m0 x1 h4 y66 ff2 fs2 fc3 sc0 lsd ws0">接<span class="ff7">器<span class="_ _0"></span></span>的<span class="ffc ls2">引<span class="ls3">脚</span>分配<span class="ff2">与<span class="_ _3"> </span><span class="ff4">DB-25<span class="_ _3"> </span></span></span>型<span class="ls3">引脚<span class="ff2">信<span class="_ _0"></span><span class="ff7">号</span></span>完</span><span class="ff2">全不同<span class="ff7">。<span class="_ _10"></span><span class="ffa ls3">因此<span class="ff2">，<span class="_ _10"></span><span class="ffc">若<span class="_ _0"></span><span class="ff2">与<span class="_ _0"></span></span>配<span class="ff2">接<span class="_ _6"> </span><span class="ff4 ls2">DB-25<span class="_ _4"> </span><span class="ffc">型<span class="ffa">连<span class="ff2">接<span class="ff7">器</span>的<span class="_ _3"> </span></span></span></span>D<span class="ls3">CE<span class="_ _3"> </span></span><span class="ff7">设备</span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y67 ffa fs2 fc3 sc0 ls2 ws0">连<span class="ff2">接，<span class="ffc">必须<span class="ff7">使用</span>专门<span class="_ _e"></span><span class="ff2">的电<span class="ffa">缆</span>线<span class="ff7">。<span class="ff4"> <span class="fc0"> </span></span></span></span></span></span></div><div class="t m0 x7 h4 y68 ff2 fs2 fc3 sc0 ls2 ws0">电<span class="ffa">缆<span class="ffc">长度</span></span>：<span class="_ _1"></span><span class="ff7">在<span class="ff2 ls3">通信</span>速率<span class="ffc">低</span>于<span class="_ _3"> </span><span class="ff4">20kb<span class="ls3">/s<span class="_ _3"> </span><span class="ffc">时<span class="_ _0"></span><span class="ff2">，<span class="_ _10"></span><span class="ff4 ls2">RS-<span class="ls3">2</span>32C<span class="_ _3"> </span><span class="ff2">所<span class="ffc">直</span>接<span class="ffa">连</span>接的<span class="ffa">最<span class="_ _e"></span><span class="ffc">大<span class="ffa">物<span class="ff2">理</span></span><span class="ls3">距离<span class="_ _0"></span><span class="ff2">为<span class="_ _3"> </span></span></span><span class="ff4">15m<span class="_ _1"></span><span class="ffa">（<span class="ff4">50</span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y69 ffc fs2 fc3 sc0 ls2 ws0">英尺<span class="ff7">）。<span class="ff4"> <span class="fc0"> </span></span></span></div><div class="t m0 x7 h4 y6a ffa fs2 fc3 sc0 ls2 ws0">最<span class="ffc">大直<span class="ff2">接<span class="ff7 ls3">传输</span></span>距离</span>说<span class="ff2">明：<span class="_ _8"></span><span class="ff4">RS-<span class="ls3">2</span>32C<span class="_ _3"> </span><span class="ff7">标准<span class="ff2">规</span>定<span class="ff2">，<span class="_ _13"></span><span class="ffc">若<span class="ff2">不<span class="ff7 ls3">使用<span class="_ _3"> </span></span><span class="ff4">MODEM</span>，<span class="_ _13"></span><span class="ff7">在<span class="ffa">码<span class="ffc">元<span class="ls3">畸</span>变小</span></span>于<span class="_ _3"> </span><span class="ff4">4%<span class="ff2">的<span class="ffc">情</span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y6b ffc fs2 fc3 sc0 ls2 ws0">况下<span class="ff2">，<span class="_ _e"></span><span class="ff4">DTE<span class="_ _3"> </span><span class="ff2">和<span class="_ _3"> </span></span>DCE<span class="_ _3"> </span><span class="ffa ls3">之<span class="ls2">间最<span class="ffc">大</span></span><span class="ff7">传输</span></span><span class="ffc">距离<span class="ff2">为<span class="_ _3"> </span></span></span>15m<span class="_ _e"></span><span class="ffa">（<span class="ff4 ls3">50<span class="_ _3"> </span></span><span class="ffc">英尺<span class="ff7 ls17">）。</span>可见<span class="_ _5"></span><span class="ff7">这个<span class="ffa">最<span class="ffc">大<span class="ff2">的</span>距离</span></span><span class="ls3">是在<span class="ffa">码</span></span><span class="ffc">元<span class="ls3">畸变</span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y6c ffc fs2 fc3 sc0 ls3 ws0">小<span class="ff7">于<span class="_ _6"> </span><span class="ff4 ls2">4%<span class="ff2">的<span class="ff7">前<span class="ffa">提<span class="ffc">下给出<span class="_ _e"></span><span class="ff2">的<span class="ff7">。</span>为<span class="ff7">了<span class="ffc">保证<span class="ffa">码</span><span class="ls3">元</span>畸变小<span class="_ _5"></span><span class="ff7">于<span class="_ _3"> </span><span class="ff4">4%<span class="ff2">的<span class="ffa">要求</span>，<span class="ls3">接口</span></span></span>标准在<span class="ff2">电<span class="ffa">气</span></span>特性<span class="_ _e"></span><span class="ffa">中<span class="ff2">规<span class="ff7">定</span>，</span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y6d ffc fs2 fc3 sc0 ls2 ws0">驱<span class="ff7">动器<span class="ff2">的负</span></span>载<span class="ff2">电<span class="ff7">容应<span class="_ _e"></span><span class="ffc">小<span class="ff7">于<span class="_ _3"> </span><span class="ff4">250<span class="ls3">0</span>pF</span>。<span class="ff4"> <span class="fc0"> </span></span></span></span></span></span></div><div class="t m0 x7 h4 y6e ff4 fs2 fc3 sc0 ls2 ws0">3<span class="ff7">、</span>RS-232C<span class="_ _4"> </span><span class="ff2">的接口信<span class="ff7">号</span></span> <span class="fc0"> </span></div><div class="t m0 x7 h4 y6f ff4 fs2 fc3 sc0 ls2 ws0">RS-232C<span class="_ _3"> </span><span class="ff2">规<span class="ff7 ls3">标准</span>接<span class="ls3">口有<span class="_ _6"> </span></span></span>25<span class="_ _3"> </span><span class="ffc">条<span class="ff2 ls3">线，<span class="_ _7"></span><span class="ff4">4<span class="_ _6"> </span><span class="ffc">条<span class="ff7 ls2">数据<span class="ff2">线</span>、<span class="_ _c"></span><span class="ff4">11<span class="_ _3"> </span><span class="ffc">条<span class="ff2 ls3">控<span class="ls2">制线<span class="ff7">、<span class="_ _c"></span><span class="ff4">3<span class="_ _4"> </span><span class="ffc">条<span class="ff7">定</span>时<span class="ff2">线<span class="ff7">、<span class="_ _c"></span><span class="ff4">7<span class="_ _3"> </span><span class="ffc">条<span class="ff7">备用<span class="ff2">和<span class="ffa">未</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y70 ff7 fs2 fc3 sc0 ls2 ws0">定义<span class="ff2">线，<span class="ffa">常</span></span>用<span class="ff2">的只有<span class="_ _4"> </span><span class="ff4">9<span class="_ _3"> </span><span class="ffc">根</span></span>，</span>它<span class="ffa">们</span>是<span class="ff2">：<span class="ff4"> <span class="fc0"> </span></span></span></div><div class="t m0 x7 h4 y71 ffa fs2 fc3 sc0 ls2 ws0">（<span class="ff4">1<span class="ff7">）<span class="ff2">联<span class="ffc">络</span><span class="ls3">控</span>制信</span>号<span class="ff2">线<span class="ffb sc3">：</span></span></span> <span class="fc0"> </span></span></div><div class="t m0 x8 h4 y72 ff7 fs2 fc3 sc0 ls2 ws0">数据<span class="ffd">装置</span><span class="ls3">准备<span class="ffd">好<span class="_ _0"></span><span class="ffa">（<span class="_ _0"></span></span></span></span><span class="ff4">Da<span class="ls3">t</span>a set r<span class="ls3">e</span>ady-DSR)<span class="_ _e"></span><span class="ffd">——<span class="ff2">有<span class="ffa">效<span class="ffc">时</span>（<span class="ff4">ON<span class="ff7">）</span></span>状态<span class="_ _e"></span><span class="ff2">，<span class="ffa">表</span>明<span class="_ _3"> </span><span class="ff4">M<span class="ls3">O</span>DEM<span class="_ _3"> </span><span class="ffd">处</span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y73 ff7 fs2 fc3 sc0 ls2 ws0">于<span class="ffc">可</span>以使用<span class="ff2">的<span class="ffa">状态</span></span>。<span class="ff4"> <span class="fc0"> </span></span></div><div class="t m0 x8 h4 y74 ff7 fs2 fc3 sc0 ls2 ws0">数据<span class="ffa">终</span>端<span class="ls3">准备<span class="ffd">好<span class="_ _0"></span></span></span><span class="ff4">(Data<span class="ls13"> </span>s<span class="ls3">e</span>t<span class="ls13"> </span>ready-DT<span class="ls3">R)<span class="_ _0"></span></span><span class="ffd">——<span class="ff2">有<span class="_ _e"></span><span class="ffa">效<span class="ffc">时</span>（<span class="ff4 ls3">ON<span class="_ _0"></span><span class="ff7">）<span class="_ _0"></span></span></span>状态<span class="ff2">，</span>表<span class="_ _e"></span><span class="ff2">明<span class="ff7">数据<span class="ffa">终</span>端<span class="ffc">可</span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y75 ff7 fs2 fc3 sc0 ls2 ws0">以使用。<span class="ff4"> <span class="fc0"> </span></span></div><div class="t m0 x7 h7 y76 ff7 fs2 fc1 sc0 ls2 ws0">这<span class="ffa">两</span>个<span class="ff2">信</span>号<span class="ff2">有<span class="ffc">时<span class="ffa">连到<span class="_ _e"></span><span class="ff2">电<span class="ff7">源上</span>，<span class="ff7">一上</span>电<span class="ffa ls3">就立<span class="ffc">即<span class="_ _0"></span><span class="ff2">有</span></span>效</span><span class="ff7">。这<span class="ffa">两</span>个设备<span class="ffa ls3">状态<span class="ff2">信<span class="_ _0"></span><span class="ff7">号</span>有</span>效<span class="_ _0"></span></span></span>，只<span class="ffa">表<span class="ffc">示</span></span></span></span></span></span></div><div class="t m0 x1 h7 y77 ff7 fs2 fc1 sc0 ls2 ws0">设备<span class="ff2">本<span class="ffd">身<span class="ffc">可</span></span></span>用<span class="ff2">，<span class="_ _1"></span><span class="ffa">并<span class="ff2">不</span>说<span class="ff2">明通信<span class="ffd">链<span class="_ _e"></span><span class="ff2">路<span class="ffc">可<span class="ff7">以</span></span>开<span class="ffd">始<span class="ff7">进</span></span>行<span class="ls3">通信<span class="ff7">了</span>，<span class="_ _13"></span><span class="ff7">能<span class="ffd">否<span class="_ _0"></span><span class="ff2">开</span>始</span>进<span class="_ _0"></span><span class="ff2 ls2">行通信<span class="ffa">要<span class="ff7">由<span class="ffc">下面<span class="_ _e"></span><span class="ff2">的控制</span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x1 h4 y78 ff2 fs2 fc1 sc0 ls2 ws0">信<span class="ff7">号<span class="ffd">决</span>定。<span class="ff4 fc3"> <span class="fc0"> </span></span></span></div><div class="t m0 x8 h4 y79 ffd fs2 fc3 sc0 ls2 ws0">请<span class="ffa">求<span class="ff2">发</span>送<span class="ff4">(R<span class="ls3">e</span>quest<span class="ls10"> </span>to<span class="ls18"> </span>send-RT<span class="ls3">S)</span></span></span>——<span class="ff7">用<span class="ff2">来<span class="ffa">表<span class="ffc">示<span class="_ _a"> </span><span class="ff4 ls3">D<span class="ls2">TE<span class="_ _b"></span></span></span></span></span></span></span>请<span class="ffa">求<span class="_ _a"> </span><span class="ff4">DCE<span class="_ _b"></span><span class="ff2">发</span></span>送<span class="ff7">数据<span class="ff2">，</span></span></span></div><div class="t m0 x8 h4 y5b ffc fs2 fc3 sc0 ls2 ws0">即当<span class="ffa">终<span class="ff7">端</span>要<span class="ff2">发</span>送<span class="ff7">数据<span class="_ _e"></span><span class="ffc">时<span class="ff2">，<span class="_ _e"></span><span class="ff7">使<span class="ffd">该<span class="ff2">信</span></span>号<span class="_ _5"></span><span class="ff2">有<span class="ffa ls17">效（</span><span class="ff4">ON<span class="_ _3"> </span><span class="ffa">状态<span class="ff7">）<span class="_ _e"></span><span class="ff2">，<span class="_ _7"></span><span class="ffc">向<span class="_ _3"> </span><span class="ff4">MODEM<span class="_ _3"> </span><span class="ffd">请<span class="ffa">求<span class="ff2">发</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x8 h4 y5c ffa fs2 fc3 sc0 ls2 ws0">送<span class="ff7">。它用<span class="ff2 ls3">来<span class="ls2">控制<span class="_ _3"> </span><span class="ff4">MOD<span class="ls3">EM<span class="_ _3"> </span><span class="ff7">是<span class="_ _0"></span><span class="ffd">否<span class="_ _0"></span><span class="ffa">要</span></span>进<span class="ffc">入<span class="_ _0"></span></span></span></span></span></span>发<span class="ffa">送</span></span></span>状态<span class="ff7">。<span class="ff4"> <span class="fc0"> </span></span></span></div><div class="t m0 x8 h4 y7a ffd fs2 fc3 sc0 ls2 ws0">允许<span class="ff2">发<span class="ffa">送（<span class="ff4 ls3">C<span class="ls2">lear to</span> <span class="ls2">send-CTS<span class="ff7">）</span></span></span></span></span>——<span class="ff7">用<span class="_ _e"></span><span class="ff2">来<span class="ffa">表<span class="ffc">示<span class="_ _3"> </span><span class="ff4 ls3">D<span class="ls2">CE<span class="_ _3"> </span><span class="ff7">准备<span class="ffd">好</span></span></span></span></span></span>接收<span class="_ _3"> </span><span class="ff4 ls3">D<span class="ls2">TE</span></span></span></span></div><div class="t m0 x8 h4 y7b ff2 fs2 fc3 sc0 ls2 ws0">发来的<span class="ff7">数据</span>，<span class="ff7">是对<span class="ffd">请<span class="_ _e"></span><span class="ffa">求<span class="ff2">发</span>送<span class="ff2">信<span class="ff7">号<span class="_ _3"> </span><span class="ff4">RTS<span class="_ _3"> </span></span></span>的<span class="_ _e"></span><span class="ffd">响<span class="ff7">应<span class="ff2">信</span><span class="ls3">号。<span class="_ _0"></span><span class="ffc">当<span class="_ _3"> </span></span></span><span class="ff4">MODEM<span class="_ _3"> </span></span>已准备</span>好</span></span></span></span></span></div><div class="t m0 x8 h7 y7c ff2 fs2 fc3 sc0 ls2 ws0">接收<span class="ffa">终<span class="ff7">端传</span></span>来的<span class="ff7">数据<span class="_ _e"></span><span class="ff2">，<span class="ffa">并<span class="ffc">向<span class="ff7">前</span></span></span>发<span class="ffa">送<span class="ffc">时</span></span>，<span class="_ _e"></span><span class="ff7">使<span class="ffd">该<span class="ff2">信</span></span>号<span class="ff2">有<span class="ffa">效<span class="_ _5"></span><span class="ff2">，通知<span class="ffa">终<span class="ff7">端</span></span>开<span class="ffd">始</span></span></span></span></span></span></span></div><div class="t m0 x8 h4 y7d ffd fs2 fc3 sc0 ls2 ws0">沿<span class="ff2">发<span class="ffa">送<span class="ff7">数据</span></span>线<span class="_ _4"> </span><span class="ff4">TxD<span class="_ _3"> </span></span>发<span class="ffa">送<span class="ff7">数据。<span class="ff4"> <span class="fc0"> </span></span></span></span></span></div><div class="t m0 x7 h4 y7e ff7 fs2 fc1 sc0 ls2 ws0">这对<span class="_ _3"> </span><span class="ff4">RTS/C<span class="ls3">TS<span class="_ _3"> </span><span class="ffd">请<span class="_ _0"></span><span class="ffa">求<span class="_ _0"></span><span class="ff7">应</span></span></span></span><span class="ff2">答联<span class="ffc">络</span>信<span class="_ _e"></span><span class="ff7">号是用于<span class="ff2">半双工<span class="_ _3"> </span><span class="ff4">M<span class="ls3">O</span>DEM<span class="_ _4"> </span><span class="ffa">系统中</span></span>发<span class="ffa">送</span>方式和<span class="ls3">接</span>收方式<span class="ffa ls3">之间</span></span></span></span></span></div><div class="t m0 x1 h7 y7f ff2 fs2 fc1 sc0 ls3 ws0">的<span class="ffd">切<span class="_ _0"></span><span class="ffc">换<span class="_ _0"></span><span class="ff7 ls14">。在<span class="_ _b"> </span></span></span></span><span class="ls2">全</span>双工<span class="_ _0"></span><span class="ffa ls2">系统中<span class="_ _e"></span><span class="ff2">作发<span class="ffa">送</span><span class="ls3">方</span>式和接<span class="ls3">收</span>方式<span class="ffa">之间</span>的<span class="ffd">切<span class="ffc">换<span class="ff7 ls14">。在<span class="_ _b"> </span></span></span></span>全<span class="ls3">双工<span class="_ _0"></span></span><span class="ffa">系统中</span>，<span class="_ _8"></span><span class="ffa">因<span class="ffc">配<span class="ffd">置<span class="ff2">双</span></span>向</span></span></span></span></div><div class="t m0 x1 h4 y80 ff2 fs2 fc1 sc0 ls2 ws0">通<span class="ffd">道</span>，<span class="ffd">故</span>不<span class="ffd">需<span class="ffa">要<span class="_ _4"> </span><span class="ff4">RTS<span class="ls3">/</span>CTS<span class="_ _3"> </span></span></span></span>联<span class="ffc">络</span>信<span class="ff7">号</span>，<span class="ff7">使<span class="ffa">其<span class="ffc">变高</span></span>。<span class="_ _e"></span><span class="ff4 fc3"> <span class="fc0"> </span></span></span></div><div class="t m0 x8 h4 y81 ff2 fs2 fc3 sc0 ls2 ws0">接收线信<span class="ff7 ls3">号检<span class="ffc">出<span class="_ _0"></span></span></span><span class="ff4">(Rec<span class="ls3">e</span>ived Li<span class="ls3">n</span>e detec<span class="ls3">t</span>ion-RL<span class="ls3">S</span>D)<span class="ffd ls3">——<span class="_ _0"></span><span class="ff7">用<span class="ff2">来<span class="_ _0"></span><span class="ffa">表<span class="ffc">示<span class="_ _6"> </span><span class="ff4">D</span></span></span></span></span></span>CE</span></div><div class="t m0 x8 h4 y82 ff7 fs2 fc3 sc0 ls2 ws0">已<span class="ff2">接通通信<span class="ffd">链</span>路，<span class="ffc">告<span class="_ _e"></span><span class="ff2">知<span class="_ _3"> </span><span class="ff4">DTE<span class="_ _3"> </span><span class="ff7 ls3">准备<span class="_ _0"></span></span></span>接收<span class="ff7 ls3">数<span class="ls2">据。<span class="ffc">当</span></span></span>本<span class="_ _e"></span><span class="ffa">地<span class="ff2">的<span class="_ _3"> </span><span class="ff4">MODEM<span class="_ _3"> </span></span>收</span>到<span class="ff7">由<span class="ff2">通</span></span></span></span></span></span></div><div class="t m0 x8 h4 y83 ff2 fs2 fc3 sc0 ls2 ws0">信<span class="ffd">链</span>路<span class="ffd">另<span class="ff7 ls3">一端<span class="_ _17"></span><span class="ffa ls2">（远地<span class="ff7">）<span class="_ _17"></span><span class="ff2">的<span class="_ _3"> </span><span class="ff4">M<span class="ls3">O</span>DEM<span class="_ _3"> </span><span class="ffa">送</span></span><span class="ls3">来的<span class="ffc">载<span class="_ _0"></span><span class="ff7">波<span class="_ _0"></span></span></span>信<span class="ff7">号<span class="ffc">时<span class="_ _0"></span></span></span>，<span class="_ _17"></span><span class="ff7">使<span class="_ _3"> </span><span class="ff4 ls2">RLSD<span class="_ _3"> </span><span class="ff2">信<span class="ff7">号</span>有<span class="_ _5"></span><span class="ffa">效<span class="ff2">，</span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x8 h4 y84 ff2 fs2 fc3 sc0 ls2 ws0">通知<span class="ffa">终<span class="ff7">端<span class="ls3">准备</span></span></span>接收，<span class="ffa">并<span class="ffd">且<span class="ff7">由<span class="_ _3"> </span><span class="ff4">M<span class="ls3">O</span>DEM<span class="_ _3"> </span></span></span>将</span></span><span class="ls3">接收<span class="ffc">下<span class="_ _0"></span></span></span>来的<span class="ffc">载<span class="ff7">波<span class="_ _e"></span><span class="ff2">信<span class="ff7">号</span>解<span class="ffd">调<span class="ff7 ls3">成数<span class="_ _0"></span><span class="ffd">字</span></span></span></span></span></span></div><div class="t m0 x8 h4 y85 ffa fs2 fc3 sc0 ls3 ws0">两<span class="ff7 ls2">数据<span class="ffc">后<span class="ff2">，<span class="ffd">沿</span>接收</span></span><span class="ls3">数据<span class="ff2">线<span class="_ _6"> </span></span></span><span class="ff4">RxD<span class="_ _3"> </span><span class="ffa">送到终</span></span><span class="ls3">端。</span></span>此<span class="_ _0"></span><span class="ff2">线<span class="ffc">也<span class="ffd ls2">叫做<span class="ff7">数据<span class="ffc">载</span>波检<span class="_ _5"></span><span class="ffc">出</span></span></span></span></span></div><div class="t m0 x8 h4 y86 ff4 fs2 fc3 sc0 ls2 ws0">(Data Carr<span class="ls3">i</span>er dect<span class="ls3">e</span>ction-D<span class="ls3">CD<span class="ff7">）<span class="_ _0"></span><span class="ff2">线<span class="_ _0"></span></span>。</span> <span class="fc0"> </span></span></div><div class="t m0 x8 h4 y87 ffd fs2 fc3 sc0 ls2 ws0">振铃指<span class="ffc">示<span class="ff4">(R<span class="ls3">i</span>nging-R<span class="ls3">I)</span></span></span>——<span class="ffc">当<span class="_ _3"> </span><span class="ff4">MODEM<span class="_ _3"> </span><span class="ff2">收<span class="ffa">到</span></span></span></span>交<span class="ffc">换</span>台<span class="_ _e"></span><span class="ffa">送<span class="ff2 ls3">来的<span class="_ _0"></span></span><span class="ffd">振铃呼叫<span class="_ _e"></span><span class="ff2">信<span class="ff7">号</span></span></span></span></div><div class="t m0 x8 h4 y88 ffc fs2 fc3 sc0 ls2 ws0">时<span class="ff2">，<span class="ff7">使<span class="ffd">该</span></span>信<span class="ff7">号</span>有<span class="ffa">效（<span class="ff4 ls3">ON<span class="_ _3"> </span></span>状态<span class="ff7">）</span></span>，通知<span class="ffa">终<span class="_ _e"></span><span class="ff7">端<span class="ff2">，</span>已<span class="ffa">被<span class="ffd">呼叫<span class="_ _e"></span><span class="ff7">。<span class="ff4"> <span class="fc0"> </span></span></span></span></span></span></span></span></div><div class="t m0 x7 h4 y89 ffa fs2 fc3 sc0 ls2 ws0">（<span class="ff4">2<span class="ff7">）数据<span class="ff2">发</span></span></span>送<span class="ff2">与接<span class="ls3">收</span>线：<span class="ff4"> <span class="fc0"> </span></span></span></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.613445,0.000000,0.000000,1.613445,0.000000,0.000000]}'></div></div>
