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長途對(dui)稱通(tong)(tong)信電纜(lan)由(you)不(bu)(bu)同(tong)(tong)數量和不(bu)(bu)同(tong)(tong)絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)結(jie)構的四(si)線組(zu)構成。四(si)線組(zu)的常(chang)用(yong)形式(shi)為星絞(jiao)(jiao)組(zu)，也有的采用(yong)復(fu)對(dui)絞(jiao)(jiao)形式(shi)（圖2）。絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)有紙(zhi)帶(dai)絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)、紙(zhi)-繩(sheng)（紙(zhi)帶(dai)和紙(zhi)繩(sheng)）絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)、聚(ju)(ju)乙(yi)烯繩(sheng)-帶(dai)絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)、聚(ju)(ju)苯乙(yi)烯繩(sheng)－帶(dai)絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)和泡沫聚(ju)(ju)乙(yi)烯絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)等多(duo)種。高頻(pin)長途對(dui)稱通(tong)(tong)信電纜(lan)傳輸頻(pin)率高，所以對(dui)電纜(lan)的結(jie)構性能要求(qiu)較高。一般采用(yong)繩(sheng)－帶(dai)絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)的星絞(jiao)(jiao)四(si)線組(zu)結(jie)構。絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)材料(liao)常(chang)用(yong)聚(ju)(ju)苯乙(yi)烯、聚(ju)(ju)乙(yi)烯。紙(zhi)帶(dai)紙(zhi)繩(sheng)絕(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)一般用(yong)于252千(qian)赫以下的低頻(pin)對(dui)稱通(tong)(tong)信電纜(lan)。

電(dian)(dian)(dian)(dian)話(hua)(hua)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)是用于(yu)市(shi)內、近郊和(he)工(gong)礦企業(ye)等較小范(fan)圍的(de)(de)(de)區(qu)域電(dian)(dian)(dian)(dian)話(hua)(hua)連(lian)接的(de)(de)(de)對(dui)(dui)(dui)稱(cheng)通(tong)信(xin)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)，常稱(cheng)市(shi)內電(dian)(dian)(dian)(dian)話(hua)(hua)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)。其主要(yao)特點為(wei)(wei)對(dui)(dui)(dui)數多（最多可達數千對(dui)(dui)(dui)，一(yi)(yi)般(ban)(ban)為(wei)(wei)數百或(huo)數十對(dui)(dui)(dui)）。由(you)于(yu)使用頻率低，通(tong)信(xin)距離近，因此線(xian)(xian)徑(jing)較長途通(tong)信(xin)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)細，一(yi)(yi)般(ban)(ban)為(wei)(wei)0.5毫米。電(dian)(dian)(dian)(dian)話(hua)(hua)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)的(de)(de)(de)線(xian)(xian)組(zu)(zu)結構有對(dui)(dui)(dui)絞(jiao)(jiao)(jiao)組(zu)(zu)、星絞(jiao)(jiao)(jiao)組(zu)(zu)和(he)復(fu)對(dui)(dui)(dui)絞(jiao)(jiao)(jiao)組(zu)(zu)3種(zhong)。按其線(xian)(xian)心(xin)絕(jue)(jue)緣(yuan)和(he)護(hu)(hu)層(ceng)材(cai)料可分(fen)為(wei)(wei)紙絕(jue)(jue)緣(yuan)鉛護(hu)(hu)套(tao)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)、聚乙烯絕(jue)(jue)緣(yuan)組(zu)(zu)合(he)(he)護(hu)(hu)層(ceng)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)、油膏充填防水電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)、全塑電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)等。　電(dian)(dian)(dian)(dian)話(hua)(hua)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)中(zhong)二根絕(jue)(jue)緣(yuan)導(dao)線(xian)(xian)心(xin)按一(yi)(yi)定節距絞(jiao)(jiao)(jiao)合(he)(he)成(cheng)(cheng)對(dui)(dui)(dui)構成(cheng)(cheng)一(yi)(yi)個(ge)絕(jue)(jue)緣(yuan)線(xian)(xian)對(dui)(dui)(dui)。線(xian)(xian)對(dui)(dui)(dui)中(zhong)二根絕(jue)(jue)緣(yuan)導(dao)線(xian)(xian)心(xin)的(de)(de)(de)顏(yan)色(se)(se)不(bu)同(tong)（一(yi)(yi)般(ban)(ban)為(wei)(wei)紅(hong)色(se)(se)和(he)白(bai)色(se)(se)），以(yi)便(bian)接線(xian)(xian)時區(qu)分(fen)。電(dian)(dian)(dian)(dian)話(hua)(hua)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)的(de)(de)(de)纜(lan)(lan)(lan)(lan)心(xin)結構一(yi)(yi)般(ban)(ban)分(fen)為(wei)(wei)同(tong)心(xin)式(shi)(shi)(shi)和(he)單(dan)(dan)位(wei)式(shi)(shi)(shi)兩(liang)種(zhong)（圖3）。同(tong)一(yi)(yi)層(ceng)中(zhong)相(xiang)鄰線(xian)(xian)對(dui)(dui)(dui)的(de)(de)(de)絞(jiao)(jiao)(jiao)合(he)(he)節距應不(bu)相(xiang)同(tong)，以(yi)減小通(tong)話(hua)(hua)時的(de)(de)(de)相(xiang)互影響。在每一(yi)(yi)層(ceng)中(zhong)都設(she)有一(yi)(yi)個(ge)標志對(dui)(dui)(dui)（分(fen)別(bie)為(wei)(wei)藍(lan)色(se)(se)和(he)白(bai)色(se)(se)），便(bian)于(yu)接線(xian)(xian)時辨認。在80對(dui)(dui)(dui)以(yi)上的(de)(de)(de)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)中(zhong)往(wang)往(wang)置有預備(bei)線(xian)(xian)對(dui)(dui)(dui)以(yi)替換不(bu)合(he)(he)格線(xian)(xian)對(dui)(dui)(dui)。單(dan)(dan)位(wei)式(shi)(shi)(shi)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)以(yi)50對(dui)(dui)(dui)或(huo)100對(dui)(dui)(dui)及相(xiang)應的(de)(de)(de)預備(bei)對(dui)(dui)(dui)絞(jiao)(jiao)(jiao)合(he)(he)成(cheng)(cheng)一(yi)(yi)個(ge)基(ji)(ji)本(ben)(ben)單(dan)(dan)位(wei)，再由(you)若(ruo)干個(ge)基(ji)(ji)本(ben)(ben)單(dan)(dan)位(wei)絞(jiao)(jiao)(jiao)合(he)(he)成(cheng)(cheng)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)心(xin)。經干燥后(hou)擠壓上護(hu)(hu)套(tao)制成(cheng)(cheng)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)（見(jian)圖）。

架空(kong)敷設的電(dian)話電(dian)纜需用自承式，由鋼索承受整個電(dian)纜的重(zhong)力(li)。20世紀60年(nian)代以來，研(yan)制出(chu)在塑料電(dian)纜中(zhong)填(tian)充油膏以防止潮氣和(he)水(shui)分的防水(shui)型(xing)電(dian)纜。

為(wei)了提高通信(xin)電(dian)(dian)纜(lan)(lan)的防(fang)潮性、穩定性，20世紀(ji)70年代以來，在市內電(dian)(dian)話電(dian)(dian)纜(lan)(lan)中(zhong)廣泛采用綜合型電(dian)(dian)纜(lan)(lan)護層(ceng)(ceng)(ceng)(ceng)(ceng)。其基本類型有(you)3種。①Alpeth：纜(lan)(lan)心(xin)外(wai)(wai)擠(ji)壓(ya)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚(ju)乙烯(xi)(xi)護層(ceng)(ceng)(ceng)(ceng)(ceng)，再搭接地縱向包裹0.2毫米皺紋(wen)(wen)鋁帶(dai)，充以聚(ju)異丁烯(xi)(xi)絕緣復合物后(hou)外(wai)(wai)敷(fu)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)熱(re)塑性膠粘(zhan)層(ceng)(ceng)(ceng)(ceng)(ceng)，最外(wai)(wai)面(mian)擠(ji)壓(ya)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚(ju)乙烯(xi)(xi)護套(tao)。②Stalpeth：皺紋(wen)(wen)鋁帶(dai)外(wai)(wai)縱包一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)皺紋(wen)(wen)鋼帶(dai)，外(wai)(wai)覆(fu)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)熱(re)塑性材料(liao)，最外(wai)(wai)層(ceng)(ceng)(ceng)(ceng)(ceng)再擠(ji)壓(ya)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚(ju)乙烯(xi)(xi)護套(tao)。③Lepeth：纜(lan)(lan)心(xin)上包覆(fu)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚(ju)乙烯(xi)(xi)護套(tao)，其外(wai)(wai)敷(fu)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)粘(zhan)性熱(re)塑性材料(liao)，最外(wai)(wai)面(mian)擠(ji)壓(ya)一(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)鉛管。