[原创]232与485的区别...

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">一、什么是</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">接口？</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">(1) RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的历史和作用</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">在串行通讯时，要求通讯双方都采用一个标准接口，使不同的设备可以方便地连接起来进行</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">通讯。</span><span lang="EN-US"><font face="Times New Roman">RS-232-C</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">接口（又称</span><span lang="EN-US"><font face="Times New Roman">EIA RS-232-C</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）是目前最常用的一种串行通讯接口。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">（</span><span lang="EN-US"><font face="Times New Roman">“RS-232-C”</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">中的</span><span lang="EN-US"><font face="Times New Roman">“-C”</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">只不过表示</span><span lang="EN-US"><font face="Times New Roman">RS-232</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的版本，所以与</span><span lang="EN-US"><font face="Times New Roman">“RS-232”</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">简称是一样的）它</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">是在</span><span lang="EN-US"><font face="Times New Roman">1970 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">年由美国电子工业协会（</span><span lang="EN-US"><font face="Times New Roman">EIA</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）联合贝尔系统、调制解调器厂家及计算机终端生产</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">厂家共同制定的用于串行通讯的标准。它的全名是</span><span lang="EN-US"><font face="Times New Roman">"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">数据终端设备（</span><span lang="EN-US"><font face="Times New Roman">DTE</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）和数据通讯设备</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">（</span><span lang="EN-US"><font face="Times New Roman">DCE</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）之间串行二进制数据交换接口技术标准</span><span lang="EN-US"><font face="Times New Roman">"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">该标准规定采用一个</span><span lang="EN-US"><font face="Times New Roman">25 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">个脚的</span><span lang="EN-US"><font face="Times New Roman">DB-25 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">连接</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">器，对连接器的每个引脚的信号内容加以规定，还对各种信号的电平加以规定。后来</span><span lang="EN-US"><font face="Times New Roman">IBM</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的</span><span lang="EN-US"><font face="Times New Roman">PC </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">机将</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">简化成了</span><span lang="EN-US"><font face="Times New Roman">DB-9 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">连接器，从而成为事实标准。而工业控制的</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">口一般</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">只使用</span><span lang="EN-US"><font face="Times New Roman">RXD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">、</span><span lang="EN-US"><font face="Times New Roman">TXD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">、</span><span lang="EN-US"><font face="Times New Roman">GND </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">三条线。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">(2)RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">接口的电气特性</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">在</span><span lang="EN-US"><font face="Times New Roman">RS-232-C </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">中任何一条信号线的电压均为负逻辑关系。即：逻辑</span><span lang="EN-US"><font face="Times New Roman">"1"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">为</span><span lang="EN-US"><font face="Times New Roman">-3 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">到</span><span lang="EN-US"><font face="Times New Roman">-15V</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">；逻辑</span><span lang="EN-US"><font face="Times New Roman">"0"</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">为</span><span lang="EN-US"><font face="Times New Roman">+3 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">到</span><span lang="EN-US"><font face="Times New Roman">+15V </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">RS-232-C </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">最常用的</span><span lang="EN-US"><font face="Times New Roman">9 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">条引线的信号内容如下所示</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">DB-9&nbsp; 1&nbsp; 2&nbsp; 3&nbsp; 4&nbsp; 5&nbsp; 6&nbsp; 7&nbsp; 8&nbsp; 9</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">DB-25 8&nbsp; 3&nbsp; 2 20&nbsp; 7&nbsp; 6&nbsp; 4&nbsp; 5&nbsp; 22</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">定义</span><span lang="EN-US"><font face="Times New Roman">DCD RXD TXD DTR GND DSR RTS CTS RI</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">(3) RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">接口的物理结构</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">RS-232-C </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">接口连接器一般使用型号为</span><span lang="EN-US"><font face="Times New Roman">DB-9 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">插头座</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">通常插头在</span><span lang="EN-US"><font face="Times New Roman">DCE</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">端</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">插座在</span><span lang="EN-US"><font face="Times New Roman">DTE</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">端</span><span lang="EN-US"><font face="Times New Roman">.</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">PC </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">机的</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">口为</span><span lang="EN-US"><font face="Times New Roman">9 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">芯针插座。而波士</span><span lang="EN-US"><font face="Times New Roman">RS-232/RS-485</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">转换器的</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">为</span><span lang="EN-US"><font face="Times New Roman">DB-9 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">孔插头。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">一些设备与</span><span lang="EN-US"><font face="Times New Roman">PC </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">机连接的</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">接口</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">因为不使用对方的传送控制信号</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">只需三条接口线</span><span lang="EN-US"><font face="Times New Roman">,</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">即</span><span lang="EN-US"><font face="Times New Roman">"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">发送数据</span><span lang="EN-US"><font face="Times New Roman">TXD"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">、</span><span lang="EN-US"><font face="Times New Roman">"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">接收数据</span><span lang="EN-US"><font face="Times New Roman">RXD"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">和</span><span lang="EN-US"><font face="Times New Roman">"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">信号地</span><span lang="EN-US"><font face="Times New Roman">GND"</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">传输线采用屏蔽双绞线。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">（</span><span lang="EN-US"><font face="Times New Roman">4</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">传输电缆长度</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">由</span><span lang="EN-US"><font face="Times New Roman">RS-232C </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">标准规定在码元畸变小于</span><span lang="EN-US"><font face="Times New Roman">4%</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的情况下，传输电缆长度应为</span><span lang="EN-US"><font face="Times New Roman">50 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">英尺，其实这个</span><span lang="EN-US"><font face="Times New Roman">4%</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的码元畸变是很保守的，在实际应用中，约有</span><span lang="EN-US"><font face="Times New Roman">99%</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的用户是按码元畸变</span><span lang="EN-US"><font face="Times New Roman">10-20%</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的范围工作的，</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">所以实际使用中最大距离会远超过</span><span lang="EN-US"><font face="Times New Roman">50</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">英尺，美国</span><span lang="EN-US"><font face="Times New Roman">DEC</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">公司曾规定允许码元畸变为</span><span lang="EN-US"><font face="Times New Roman">10%</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">而得出</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">下面实验结果。其中</span><span lang="EN-US"><font face="Times New Roman">1 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">号电缆为屏蔽电缆，型号为</span><span lang="EN-US"><font face="Times New Roman">DECP.NO.9107723 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">内有三对双绞线，每对</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">由</span><span lang="EN-US"><font face="Times New Roman">22# AWG </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">组成，其外覆以屏蔽网。</span><span lang="EN-US"><font face="Times New Roman">2 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">号电缆为不带屏蔽的电缆。型号为</span><span lang="EN-US"><font face="Times New Roman">DECP.NO.9105856-04</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">是</span><span lang="EN-US"><font face="Times New Roman">22#AWG </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的四芯电缆。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">DEC </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">公司的实验结果</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">波特率</span><span lang="EN-US"><font face="Times New Roman">bps&nbsp; 1</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">号电缆传输距离（米）</span><span lang="EN-US"><font face="Times New Roman"> 2</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">号电缆传输距离（米）</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;110&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1500&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 900</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;300&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1500&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 900</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;1200&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 900&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 900</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;2400&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 300&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 150</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;4800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 300&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 75</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;9600&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 75&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 75</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">经过许多年来</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">器件以及通信技术的改进，</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的通信距离已经大大增加。波士</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电子的</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">增强器可以将普通的</span><span lang="EN-US"><font face="Times New Roman">RS-232 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">口的通信距离直接延长到</span><span lang="EN-US"><font face="Times New Roman">1000</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">米。</span></p>

<div id="textstyle_20" style="FONT-SIZE: 9pt; OVERFLOW: hidden; WORD-BREAK: break-all; TEXT-INDENT: 24px; WORD-WRAP: break-word">长见识 </div>

<p>学习了</p>

<p>还是不太懂</p>

&nbsp;485呢？

以前了解过一点，没想到这么深奥

<p>诶！怎么不讲485呢？</p>

讲得太专业了点了..

怎么没看到485的介绍啊，还是谢谢楼主

有点太专业了

专业

<p>不是太全</p>

<p>顶 学习下</p>

好啊

请继续呀，把485也讲一讲，谢谢！

我有很多资料想下载学习，可是积分不够啊！支持一下！

还是没搞懂

有没有图片呢 期待中

不太理解，太理论式了，能否有高人来点经验之谈？

有点太过理论，希望有点图片，更形象一点