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标题:
综合布线：超五类网线和六类网线的选购
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作者:
ltcx95
时间:
2008-6-10 16:51
标题:
综合布线：超五类网线和六类网线的选购
<font face="宋体" size="3">目前，局域网中常用到的双绞线一般都是非屏蔽的5类4对（即8根导线）的电缆线。这些双绞线的传输速率都能达到100Mbps。 <br/><br/> 市场上出售的3类双绞线外层保护胶皮薄，胶皮上标注“CAT3”字样，外包装纸箱上标注有“3类”字样，售价较低；5类双绞线外层保护胶皮厚，胶皮上标注“CAT5”字样，外包装纸箱上标注有“5类”字样，售价较高。购买时切勿图便宜而购买劣质5类双绞线，这些产品往往只能作为3类双绞线使用。 <br/><br/> 超5类双绞线属非屏蔽双绞线。与普通5类双绞线比较，超5类双绞线在传送信号时衰减更小，抗干扰能力更强。在100M网络中，用户设备的受干扰程度只有普通5类线的1/4，是为网络应用提供的理想解决方案。 <br/><br/> "超五类"指的是超五类非屏蔽双绞线(UTP—UnshieldedTwistedPair) <br/><br/> 非屏蔽双绞线电缆是由多对双绞线和一个塑料外皮构成。五类是指国际电气工业协会为双绞线电缆定义的五种不同的质量级别。 <br/><br/> 超五类非屏蔽双绞线是在对现有五类屏蔽双绞线的部分性能加以改善后出现的电缆，不少性能参数，如近端串扰、衰减串扰比，回波损耗等都有所提高，但其传输带宽仍为100MHz。 <br/><br/> 超五类双绞线也是采用4个绕对和1条抗拉线，线对的颜色与五类双绞线完全相同，分别为白橙、橙、白绿、绿、白蓝、蓝、白棕和棕。裸铜线径为0.51mm（线规为24AWG），绝缘线径为0.92mm，UTP电缆直径为5mm。 <br/><br/> 超五类双绞线通常只被应用于100Mb/s快速以太网，实现桌面交换机到计算机的连接。如果想以后将网络升级为千兆以太网，那么不妨在水平布线中采用超五类非屏蔽双绞线。超五类非屏蔽双绞线也能提供高达1000Mb/s的传输带宽，但是往往需要借助于价格高昂的特殊设备的支持。 <br/><br/> 超五类还是六类 <br/><br/> "六类"是指六类非屏蔽双绞线 <br/><br/> 六类非屏蔽双绞线的各项参数都有大幅提高，带宽也扩展至250MHz或更高。六类双绞线在外形上和结构上与五类或超五类双绞线都有一定的差别，不仅增加了绝缘的十字骨架，将双绞线的四对线分别置于十字骨架的四个凹槽内，而且电缆的直径也更粗。 <br/><br/> 电缆中央的十字骨架随长度的变化而旋转角度，将四对双绞线卡在骨架的凹槽内，保持四对双绞线的相对位置，提高电缆的平衡特性和串扰衰减。另外，保证在安装过程中电缆的平衡结构不遭到破坏。六类非屏蔽双绞线裸铜线径为0.57mm（线规为23AWG），绝缘线径为1.02mm，UTP电缆直径为6.53mm。 <br/><br/> 按照电气性能的不同，双绞线可分为三类、五类、超五类、六类和七类双绞线。不同类别的双绞线价格相差较大甚至是悬殊，应用范围也大不相同。 <br/><br/> 除了传统的语音系统仍然使用三类双绞线以外，网络布线目前基本上都在采用超五类或六类非屏蔽双绞线。 <br/><br/> 五类非屏蔽双绞线虽仍然可以支持1000Base-T，但由于在价格上与超五类非屏蔽双绞线相差无几，因此，已经逐渐淡出布线市场。 </font><p><font face="宋体" size="3"> 六类非屏蔽双绞线虽然价格较高，但由于与超五类布线系统具有非常好的兼容性，且能够非常好地支持1000Base-T，所以正慢慢成为综合布线的新宠。七类屏蔽双绞线由于是一种全新的布线系统，虽然性能优异，但由于价格昂贵。施工复杂且可选择的产品较少，因此很少在布线工程中采用。 <br/><br/> 六类非屏蔽双绞线可以非常好地支持千兆以太网，并实现100m的传输距离。因此，六类布线系统被广泛应用子服务器机房的布线，以及保留升级至千兆以太网能力的水平布线。根据国际布线标准ISO11801，布线系统的期望寿命至少为10年。作为一种长期的基本投资，综合布线应当充分考虑网络的潜在需求和布线系统的发展，因此，在资金允许的条件下，建议选择六类产品构建布线系统。 <br/><br/> 若考虑网络将来的应用需求，理论上应安装最先进的布线产品，因为安装电缆后往往难以重新更新替代，基本上，一个布线系统至少要应用10年作为标准，能够支持4至5代的网络设备的性能更新，如果将来的网络设备需要更好的电缆才能提高数据速度。 <br/><br/> 那么，用六类电缆代替超五类电缆是无可避免的，但这些电缆重新组建工程非常昂贵，所以纵使六类产品的价格相对于超五类产品稍贵，但为了减少日后网络升级问题，六类产品仍然值得考虑。</font></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-SIZE: 16pt; COLOR: #ff99cc;"><font face="Times New Roman">http://www.95px.com<p></p></font></span></b></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 15pt; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><b><span lang="EN-US" style="FONT-SIZE: 12pt; COLOR: #0099ff; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;"> <p></p></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span style="FONT-SIZE: 12pt; COLOR: red; FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">北京市朝阳区龙腾畅晓培训学校</span></b><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-SIZE: 12pt; COLOR: red;"><p></p></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-SIZE: 12pt;"><font face="Times New Roman"> <span style="COLOR: #ff99cc;"> <p></p></span></font></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 5.9pt; mso-char-indent-count: .49; mso-char-indent-size: 12.0pt;"><b style="mso-bidi-font-weight: normal;"><span style="FONT-SIZE: 12pt; COLOR: #ff99cc; FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">学校网址：</span></b><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-SIZE: 12pt; COLOR: #ff99cc;"><font face="Times New Roman">www.95px.com<br/> </font></span></b><b style="mso-bidi-font-weight: normal;"><span style="FONT-SIZE: 12pt; COLOR: #ff99cc; FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">咨询电话：</span></b><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-SIZE: 12pt; COLOR: #ff99cc;"><font face="Times New Roman">13693689909 13693683737<span style="mso-spacerun: yes;"> </span>010-84804842 84804942<p></p></font></span></b></p><p><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="FONT-SIZE: 12pt; COLOR: #ff99cc; FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">QQ号:704860558 940436037 940415875<span style="mso-spacerun: yes;"> </span>565249462</span><span lang="EN-US" style="FONT-SIZE: 12pt; COLOR: #ff99cc; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><br style="mso-special-character: line-break;"/><br style="mso-special-character: line-break;"/></span></b></p>
作者:
ltcx95
时间:
2008-6-10 16:54
<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">北京市朝阳区龙腾畅晓培训学校</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";"></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">共开设</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">“电视监控系统集成师</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">”、</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">“安防系统集成师</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">”、</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">“安防系统集成项目经理</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">”、</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">“智能建筑弱电系统集成师</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">”、</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">“智能建筑弱电系统项目经理</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">”、</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">“楼宇自控系统集成师</span><font face="Times New Roman">
</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">”</span><span lang="EN-US"><font face="Times New Roman">6</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">门课程，面向全国招生，学习结束后</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">取得由信息产业部颁发的专项技术证书</span><span lang="EN-US"><font face="Times New Roman">.</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">学校提供</span><span lang="EN-US"><font face="Times New Roman">1-3</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">个月实习期</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">一年免费推荐工作</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"> <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">上课地点：北京朝阳区安慧北里二区北辰培训中心</span><span lang="EN-US"><font face="Times New Roman">156</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">室（亚运村北辰购物中心对面）。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"> <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">咨询电话：</span><span lang="EN-US"><font face="Times New Roman"> 13693689909</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">、</span><span lang="EN-US"><font face="Times New Roman"> 13693683737 0</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">、</span><span lang="EN-US"><font face="Times New Roman">0 10-84804842</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">、</span><span lang="EN-US"><font face="Times New Roman"> 010-84804942</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">（</span><span lang="EN-US"><font face="Times New Roman"> 8</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">：</span><span lang="EN-US"><font face="Times New Roman"> 30</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">－</span><span lang="EN-US"><font face="Times New Roman"> 17:30</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">）</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"> <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">咨询报名</span><span lang="EN-US"><font face="Times New Roman"> QQ</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">：</span><span lang="EN-US"><font face="Times New Roman"> 940415875</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">、</span><span lang="EN-US"><font face="Times New Roman"> 940436037</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">、</span><span lang="EN-US"><font face="Times New Roman"> 565249462</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">、</span><span lang="EN-US"><font face="Times New Roman"> 704860558 </font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"> <p></p></font></span></p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">学校网址：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">http://www.95px.com<span style="mso-spacerun: yes;"> </span></span>
作者:
ltcx95
时间:
2008-6-19 16:46
<p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt; mso-hansi-font-family: "Times New Roman";">课程结合实际施工、经验传达给学员，</span></p><p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt; mso-hansi-font-family: "Times New Roman";">上课期间学员相互间可就某方面问题相互之间、或与老师之间及时沟通，有助于及时深刻了解。</span></p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt; mso-hansi-font-family: "Times New Roman";"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">咨询电话：</span><span lang="EN-US"><font face="Times New Roman"> 13693689909</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">、</span><span lang="EN-US"><font face="Times New Roman"> 13693683737 0</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">、</span><span lang="EN-US"><font face="Times New Roman">0 10-84804842</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">、</span><span lang="EN-US"><font face="Times New Roman"> 010-84804942</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">（</span><span lang="EN-US"><font face="Times New Roman"> 8</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">：</span><span lang="EN-US"><font face="Times New Roman"> 30</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">－</span><span lang="EN-US"><font face="Times New Roman"> 17:30</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">）</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"> <p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">咨询报名</span><span lang="EN-US"><font face="Times New Roman"> QQ</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">：</span><span lang="EN-US"><font face="Times New Roman"> 940415875</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">、</span><span lang="EN-US"><font face="Times New Roman"> 940436037</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">、</span><span lang="EN-US"><font face="Times New Roman"> 565249462</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'mso-hansi-font-family:';">、</span><span lang="EN-US"><font face="Times New Roman"> 704860558 </font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman"> <p></p></font></span></p><p></p><p></p><p><span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'mso-ascii-font-family:'mso-hansi-font-family:'mso-ansi-language:en-us;mso-fareast-language:zh-cn;mso-bidi-language:ar-sa;; mso-bidi-font-size: 12.0pt;">学校网址：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'mso-bidi-font-size:12.0pt;mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:en-us;mso-fareast-language:zh-cn;mso-bidi-language:ar-sa;;">http://www.95px.com<span style="mso-spacerun: yes;"> </span></span><br/><a href="http://www.1000bbs.com/dispbbs.asp?boardid=25&id=309076&star=1&page=1"></a></p></span><a href="http://www.1000bbs.com/dispbbs.asp?boardid=25&id=309076&star=1&page=1"></a>
作者:
wxxcnn
时间:
2011-1-14 22:47
很好
作者:
右边
时间:
2011-1-14 23:47
学习。。。
作者:
dnvso
时间:
2011-1-15 11:53
<p>非常的好呀</p>
作者:
西贝线缆
时间:
2011-1-15 15:17
楼主辛苦了，
作者:
hzq8109
时间:
2011-1-15 20:36
这个真的学习了
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