淺談光纖光纜、網線、電(dian)纜的區(qu)別

 在(zai)網絡硬件中，有一類網絡傳(chuan)輸介質，我們通常(chang)稱為(wei)網線。目前比(bi)較常(chang)見的網線分細雙(shuang)絞線、光纖光纜(lan)、同軸線纜(lan)和(he)粗同軸線纜(lan)等。

　　 1.光纖光纜

　　光(guang)(guang)纖(xian)(xian)(xian)(xian)光(guang)(guang)纜是(shi)新(xin)一代(dai)的(de)(de)(de)傳(chuan)輸(shu)(shu)介質，與(yu)銅質介質相比(bi)(bi)，光(guang)(guang)纖(xian)(xian)(xian)(xian)無論是(shi)在(zai)安(an)全性(xing)(xing)、可靠(kao)性(xing)(xing)還是(shi)網絡性(xing)(xing)能方面都有(you)了(le)很大的(de)(de)(de)提(ti)高(gao)。除此(ci)之(zhi)外，光(guang)(guang)纖(xian)(xian)(xian)(xian)傳(chuan)輸(shu)(shu)的(de)(de)(de)帶寬大大超出銅質線纜，而(er)且其支持(chi)的(de)(de)(de)大連接(jie)(jie)距(ju)離達(da)兩(liang)公里(li)以上，是(shi)組建(jian)較(jiao)(jiao)大規模網絡的(de)(de)(de)必然選擇。由于(yu)光(guang)(guang)纖(xian)(xian)(xian)(xian)光(guang)(guang)纜具有(you)抗電磁干擾(rao)性(xing)(xing)好、保(bao)密性(xing)(xing)強、速度快、傳(chuan)輸(shu)(shu)容量大等優點，所以它的(de)(de)(de)價格也較(jiao)(jiao)為(wei)昂貴，在(zai)家用場合(he)很少(shao)使(shi)(shi)用。目(mu)前比(bi)(bi)較(jiao)(jiao)常見的(de)(de)(de)有(you)兩(liang)種(zhong)不同類型(xing)的(de)(de)(de)光(guang)(guang)纖(xian)(xian)(xian)(xian)，分別是(shi)單模光(guang)(guang)纖(xian)(xian)(xian)(xian)和(he)多模光(guang)(guang)纖(xian)(xian)(xian)(xian)（所謂"模"就是(shi)指以一定(ding)的(de)(de)(de)角度進入光(guang)(guang)纖(xian)(xian)(xian)(xian)的(de)(de)(de)一束光(guang)(guang)線）。多模光(guang)(guang)纖(xian)(xian)(xian)(xian)一般(ban)被用于(yu)同一辦公樓(lou)或距(ju)離相對較(jiao)(jiao)近的(de)(de)(de)區域內的(de)(de)(de)網絡連接(jie)(jie)。而(er)單模光(guang)(guang)纖(xian)(xian)(xian)(xian)傳(chuan)遞數據的(de)(de)(de)質量更(geng)高(gao)，傳(chuan)輸(shu)(shu)距(ju)離更(geng)長(chang)，通(tong)常被用來連接(jie)(jie)辦公樓(lou)之(zhi)間或地理分散更(geng)廣的(de)(de)(de)網絡。如(ru)果使(shi)(shi)用光(guang)(guang)纖(xian)(xian)(xian)(xian)光(guang)(guang)纜作為(wei)網絡傳(chuan)輸(shu)(shu)介質，還需增加(jia)光(guang)(guang)端收(shou)發器等設(she)備(bei)，因此(ci)成本投入更(geng)大，在(zai)一般(ban)的(de)(de)(de)應用中較(jiao)(jiao)少(shao)采用。

　　 2.雙絞線

　　雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)是一(yi)(yi)種柔性的(de)通信電纜，包含著成對的(de)絕(jue)緣銅(tong)線(xian)(xian)(xian)(xian)，它的(de)特點(dian)是價(jia)格便宜，所(suo)(suo)(suo)以(yi)(yi)被廣泛應(ying)用(yong)，如我們常(chang)(chang)(chang)見的(de)電hua線(xian)(xian)(xian)(xian)等。根據大傳輸速率(lv)的(de)不同，雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)可(ke)(ke)分為(wei)(wei)3類(lei)、5類(lei)及超5類(lei)。3類(lei)雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)的(de)速率(lv)為(wei)(wei)10mb/s，5類(lei)可(ke)(ke)達100mb/s，而(er)超5類(lei)則高達155mb/s以(yi)(yi)上(shang)，可(ke)(ke)以(yi)(yi)適合(he)未來多(duo)媒(mei)體數據傳輸的(de)需求，所(suo)(suo)(suo)以(yi)(yi)推薦采用(yong)5類(lei)甚至超5類(lei)雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)。雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)還(huan)可(ke)(ke)分為(wei)(wei)屏(ping)蔽雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)（stp）和(he)非屏(ping)蔽雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)（utp）。stp雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)雖(sui)然(ran)速率(lv)較低(di)（只有4mb/s），但抗干擾性比(bi)utp雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)強，所(suo)(suo)(suo)以(yi)(yi)價(jia)格也要(yao)貴(gui)許多(duo)，現在(zai)這類(lei)雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)便宜的(de)幾元(yuan)一(yi)(yi)米，貴(gui)的(de)嘛可(ke)(ke)能十(shi)幾元(yuan)以(yi)(yi)上(shang)才能買到(dao)(dao)一(yi)(yi)米。相(xiang)比(bi)之下，utp雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)價(jia)格一(yi)(yi)般在(zai)一(yi)(yi)米一(yi)(yi)元(yuan)左右，比(bi)較低(di)廉。另外，常(chang)(chang)(chang)用(yong)的(de)10m和(he)100m非屏(ping)蔽雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)的(de)流(liu)行叫(jiao)法是10base-t和(he)100base-t，大家在(zai)市面上(shang)經(jing)常(chang)(chang)(chang)可(ke)(ke)以(yi)(yi)見到(dao)(dao)。和(he)雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)配套使(shi)用(yong)的(de)還(huan)有rj45水晶(jing)頭，用(yong)于制作雙(shuang)(shuang)絞(jiao)(jiao)線(xian)(xian)(xian)(xian)與網卡rj45接口間的(de)接頭，其質量(liang)好壞直接關(guan)系到(dao)(dao)整個網絡的(de)穩(wen)定性，不可(ke)(ke)忽視。

　　 3.同軸電纜

　　同(tong)軸電(dian)(dian)纜(lan)(lan)是(shi)很多(duo)(duo)朋友比(bi)較熟悉(xi)的(de)一(yi)類傳輸(shu)介(jie)質，它是(shi)由一(yi)層(ceng)層(ceng)的(de)絕緣線(xian)包裹著(zhu)*銅(tong)導(dao)體的(de)電(dian)(dian)纜(lan)(lan)線(xian)，它的(de)大特點就(jiu)是(shi)抗干擾能力好，傳輸(shu)數據穩定，而(er)且價格(ge)也便宜，所以一(yi)度(du)被廣泛使用(yong)(yong)(yong)，如(ru)閉路電(dian)(dian)視線(xian)等。然而(er)以前同(tong)軸電(dian)(dian)纜(lan)(lan)采用(yong)(yong)(yong)較多(duo)(duo)，主要是(shi)因為同(tong)軸電(dian)(dian)纜(lan)(lan)組成(cheng)的(de)總線(xian)結構(gou)網絡(luo)成(cheng)本較低，但單條電(dian)(dian)纜(lan)(lan)的(de)損壞可能導(dao)致整(zheng)個網絡(luo)崩潰，維護也難，這是(shi)其大的(de)弊端(duan)。以太(tai)(tai)網應用(yong)(yong)(yong)中(zhong)的(de)同(tong)軸電(dian)(dian)纜(lan)(lan)主要分(fen)為粗同(tong)軸電(dian)(dian)纜(lan)(lan)（10base5）和細(xi)同(tong)軸電(dian)(dian)纜(lan)(lan)（10base2）兩(liang)種。現在粗同(tong)軸電(dian)(dian)纜(lan)(lan)用(yong)(yong)(yong)得不多(duo)(duo)了，細(xi)同(tong)軸電(dian)(dian)纜(lan)(lan)還有些市場(chang)(chang)(chang)。細(xi)同(tong)軸電(dian)(dian)纜(lan)(lan)線(xian)一(yi)般(ban)市場(chang)(chang)(chang)售(shou)價幾(ji)元一(yi)米，不算太(tai)(tai)貴。另(ling)外，同(tong)軸電(dian)(dian)纜(lan)(lan)是(shi)用(yong)(yong)(yong)來和bnc頭相連的(de)，市場(chang)(chang)(chang)上賣的(de)同(tong)軸電(dian)(dian)纜(lan)(lan)線(xian)一(yi)般(ban)都是(shi)已(yi)和bnc頭連接(jie)好了的(de)成(cheng)品，大家可直接(jie)選用(yong)(yong)(yong)。