通信人家园
标题:
[原创]485网络通讯方式分析（2）
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时间:
2008-2-26 15:48
作者:
monsoon
标题:
[原创]485网络通讯方式分析（2）
<p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">7</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。什么叫共模干扰和差模干扰？如何消除通讯线上的干扰？</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman"> 485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通信线由两根双绞的线组成，它是通过两根通信线之间的电压差的方式来传递信号，因此称之为差分电压传输。</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">差模干扰在两根信号线之间传输，属于对称性干扰。消除差模干扰的方法是在电路中增加一个偏值电阻</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">,</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">并采用双绞线；</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">共模干扰是在信号线与地之间传输，属于非对称性干扰。消除共模干扰的方法包括：（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">1</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）采用屏蔽双绞线并有效接地（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">2</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）强电场的地方还要考虑采用镀锌管屏蔽（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">3</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）布线时远离高压线，更不能将高压电源线和信号线捆在一起走线（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">4</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）不要和电控锁共用同一个电源（</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">5</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">）采用线性稳压电源或高品质的开关电源</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">(</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">纹波干扰小于</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">50mV) <p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">8</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。什么情况下在</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">总线上要增加终端电阻？</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman"> </font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">一般情况下不需要增加终端电阻，只有在</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通信距离超过</span><chmetcnv wst="on" unitname="米" sourcevalue="300" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">300</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">米</span></chmetcnv><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">的情况下，要在</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">通讯的开始端和结束端增加终端电阻。尤其是</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">总线上设备数量较少时。当设备数量较多时（如超过</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">22</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">台）。一般不需增加终端电阻，因为终端电阻会降低</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">总线的负载能力。当需要增加终端电阻时，只要将控制器上面的终端电阻跳线置位既可，如果另一端连接的是计算机的话，同时将</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">转换器的棕色和白色短路。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">
<p></p></font></span></p><p class="MsoNormal" align="left" style="MARGIN: 3pt 0cm 7.5pt; WORD-BREAK: break-all; LINE-HEIGHT: 18pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">9</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">。如何延长</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><font face="Times New Roman">485</font></span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥;">的通讯距离</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-font-kerning: 0pt; mso-bidi-font-family: Arial;"><p></p></span></p><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"> 485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">网络的规范之一是</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">1.2</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">公里长度，</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">32</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">个节点数。如果超出了这个限制，那么必须采用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器来拓展网络距离或节点数。</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">
</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"> 利用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器，可以将一个大型</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">网络分隔成若干个网段。</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器就如同</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">网段之间连接的</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">"</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">桥梁</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">"</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">。当然每个网段还是遵循上面的</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">规范，即</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">1.2</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">公里长度，</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">32</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">个节点数。 </span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">
</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">利用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器延长网络距离图示：</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">
</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">利用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器解决</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">分叉问题，如图所示：</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">
</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">利用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器构造星型</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">网络</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"> 485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器是</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">中继器概念的拓广，它不仅解决了多分叉问题，同时也解决了网段之间相互隔离的问题，即某一个网段出现问题（例如短路等），不至于影响到其它网段，从而极大地提高了大型网络的安全性和稳定性。</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">
</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">我们可以从局域网从总线型到星型的发展历程，来体会星型布线网络给我们带来的好处。同样，采用</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">集线器构成的星型</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">网络也将是</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: ˎ̥; mso-fareast-font-family: 宋体; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">网络发展的一个方向。</span></font>
时间:
2008-2-26 19:27
作者:
永远888
学习了
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