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長(chang)途對(dui)稱通(tong)信電(dian)纜(lan)由不(bu)同(tong)數量和(he)不(bu)同(tong)絕(jue)(jue)(jue)緣(yuan)(yuan)結(jie)構(gou)的四(si)線(xian)組(zu)構(gou)成。四(si)線(xian)組(zu)的常用(yong)(yong)(yong)形(xing)式為(wei)星(xing)絞(jiao)(jiao)(jiao)組(zu)，也有的采(cai)用(yong)(yong)(yong)復對(dui)絞(jiao)(jiao)(jiao)形(xing)式（圖2）。絕(jue)(jue)(jue)緣(yuan)(yuan)有紙帶(dai)(dai)絕(jue)(jue)(jue)緣(yuan)(yuan)、紙-繩(sheng)（紙帶(dai)(dai)和(he)紙繩(sheng)）絕(jue)(jue)(jue)緣(yuan)(yuan)、聚(ju)乙(yi)(yi)烯(xi)繩(sheng)-帶(dai)(dai)絕(jue)(jue)(jue)緣(yuan)(yuan)、聚(ju)苯(ben)(ben)乙(yi)(yi)烯(xi)繩(sheng)－帶(dai)(dai)絕(jue)(jue)(jue)緣(yuan)(yuan)和(he)泡沫聚(ju)乙(yi)(yi)烯(xi)絕(jue)(jue)(jue)緣(yuan)(yuan)等多種。高頻長(chang)途對(dui)稱通(tong)信電(dian)纜(lan)傳輸頻率(lv)高，所以對(dui)電(dian)纜(lan)的結(jie)構(gou)性能要求較高。一般(ban)采(cai)用(yong)(yong)(yong)繩(sheng)－帶(dai)(dai)絕(jue)(jue)(jue)緣(yuan)(yuan)的星(xing)絞(jiao)(jiao)(jiao)四(si)線(xian)組(zu)結(jie)構(gou)。絕(jue)(jue)(jue)緣(yuan)(yuan)材(cai)料(liao)常用(yong)(yong)(yong)聚(ju)苯(ben)(ben)乙(yi)(yi)烯(xi)、聚(ju)乙(yi)(yi)烯(xi)。紙帶(dai)(dai)紙繩(sheng)絕(jue)(jue)(jue)緣(yuan)(yuan)一般(ban)用(yong)(yong)(yong)于252千(qian)赫(he)以下的低頻對(dui)稱通(tong)信電(dian)纜(lan)。

電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)是用于市內(nei)、近郊和(he)(he)工(gong)礦企業等較(jiao)(jiao)小(xiao)范圍的(de)區域(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)連接的(de)對(dui)(dui)(dui)(dui)(dui)(dui)稱通信(xin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)，常稱市內(nei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)。其主要特點為(wei)對(dui)(dui)(dui)(dui)(dui)(dui)數(shu)多（最(zui)多可(ke)達數(shu)千對(dui)(dui)(dui)(dui)(dui)(dui)，一(yi)(yi)(yi)(yi)般(ban)為(wei)數(shu)百或(huo)數(shu)十(shi)對(dui)(dui)(dui)(dui)(dui)(dui)）。由于使用頻率低，通信(xin)距離近，因此線(xian)(xian)徑較(jiao)(jiao)長途(tu)通信(xin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)細，一(yi)(yi)(yi)(yi)般(ban)為(wei)0.5毫米(mi)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)的(de)線(xian)(xian)組結構有(you)對(dui)(dui)(dui)(dui)(dui)(dui)絞(jiao)(jiao)組、星絞(jiao)(jiao)組和(he)(he)復(fu)對(dui)(dui)(dui)(dui)(dui)(dui)絞(jiao)(jiao)組3種。按其線(xian)(xian)心(xin)絕緣(yuan)和(he)(he)護層材料可(ke)分(fen)為(wei)紙絕緣(yuan)鉛護套電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)、聚(ju)乙烯絕緣(yuan)組合(he)(he)護層電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)、油膏充填防水電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)、全塑電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)等。　電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)中(zhong)二(er)(er)根絕緣(yuan)導(dao)線(xian)(xian)心(xin)按一(yi)(yi)(yi)(yi)定節距絞(jiao)(jiao)合(he)(he)成(cheng)對(dui)(dui)(dui)(dui)(dui)(dui)構成(cheng)一(yi)(yi)(yi)(yi)個(ge)絕緣(yuan)線(xian)(xian)對(dui)(dui)(dui)(dui)(dui)(dui)。線(xian)(xian)對(dui)(dui)(dui)(dui)(dui)(dui)中(zhong)二(er)(er)根絕緣(yuan)導(dao)線(xian)(xian)心(xin)的(de)顏色(se)(se)不同（一(yi)(yi)(yi)(yi)般(ban)為(wei)紅色(se)(se)和(he)(he)白色(se)(se)），以(yi)便(bian)接線(xian)(xian)時區分(fen)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)的(de)纜(lan)(lan)心(xin)結構一(yi)(yi)(yi)(yi)般(ban)分(fen)為(wei)同心(xin)式(shi)和(he)(he)單位式(shi)兩(liang)種（圖3）。同一(yi)(yi)(yi)(yi)層中(zhong)相(xiang)鄰線(xian)(xian)對(dui)(dui)(dui)(dui)(dui)(dui)的(de)絞(jiao)(jiao)合(he)(he)節距應不相(xiang)同，以(yi)減小(xiao)通話(hua)時的(de)相(xiang)互影響。在(zai)每一(yi)(yi)(yi)(yi)層中(zhong)都設有(you)一(yi)(yi)(yi)(yi)個(ge)標志對(dui)(dui)(dui)(dui)(dui)(dui)（分(fen)別為(wei)藍色(se)(se)和(he)(he)白色(se)(se)），便(bian)于接線(xian)(xian)時辨(bian)認。在(zai)80對(dui)(dui)(dui)(dui)(dui)(dui)以(yi)上的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)中(zhong)往往置有(you)預(yu)備線(xian)(xian)對(dui)(dui)(dui)(dui)(dui)(dui)以(yi)替(ti)換不合(he)(he)格線(xian)(xian)對(dui)(dui)(dui)(dui)(dui)(dui)。單位式(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)以(yi)50對(dui)(dui)(dui)(dui)(dui)(dui)或(huo)100對(dui)(dui)(dui)(dui)(dui)(dui)及相(xiang)應的(de)預(yu)備對(dui)(dui)(dui)(dui)(dui)(dui)絞(jiao)(jiao)合(he)(he)成(cheng)一(yi)(yi)(yi)(yi)個(ge)基(ji)本(ben)單位，再由若干(gan)個(ge)基(ji)本(ben)單位絞(jiao)(jiao)合(he)(he)成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)心(xin)。經干(gan)燥(zao)后擠壓上護套制(zhi)成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)（見圖）。

架(jia)空(kong)敷設(she)的(de)(de)電(dian)話電(dian)纜(lan)需用自承式，由鋼索承受整個電(dian)纜(lan)的(de)(de)重力(li)。20世紀60年代以來，研(yan)制(zhi)出在塑料電(dian)纜(lan)中填充油膏以防(fang)止潮氣和水分的(de)(de)防(fang)水型電(dian)纜(lan)。

為了提(ti)高通信電(dian)纜(lan)(lan)的防(fang)潮性(xing)(xing)(xing)、穩定(ding)性(xing)(xing)(xing)，20世紀70年代以(yi)來(lai)，在市內電(dian)話電(dian)纜(lan)(lan)中廣泛采用綜(zong)合型(xing)(xing)電(dian)纜(lan)(lan)護(hu)層(ceng)(ceng)(ceng)(ceng)(ceng)。其(qi)基本類型(xing)(xing)有(you)3種(zhong)。①Alpeth：纜(lan)(lan)心外(wai)擠壓一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚乙(yi)烯(xi)護(hu)層(ceng)(ceng)(ceng)(ceng)(ceng)，再(zai)搭接(jie)地縱向(xiang)包裹0.2毫米皺(zhou)紋鋁帶，充(chong)以(yi)聚異丁烯(xi)絕緣復合物后外(wai)敷一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)熱(re)(re)(re)塑性(xing)(xing)(xing)膠(jiao)粘層(ceng)(ceng)(ceng)(ceng)(ceng)，最外(wai)面(mian)擠壓一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚乙(yi)烯(xi)護(hu)套(tao)。②Stalpeth：皺(zhou)紋鋁帶外(wai)縱包一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)皺(zhou)紋鋼帶，外(wai)覆(fu)一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)熱(re)(re)(re)塑性(xing)(xing)(xing)材(cai)料，最外(wai)層(ceng)(ceng)(ceng)(ceng)(ceng)再(zai)擠壓一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚乙(yi)烯(xi)護(hu)套(tao)。③Lepeth：纜(lan)(lan)心上包覆(fu)一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)聚乙(yi)烯(xi)護(hu)套(tao)，其(qi)外(wai)敷一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)粘性(xing)(xing)(xing)熱(re)(re)(re)塑性(xing)(xing)(xing)材(cai)料，最外(wai)面(mian)擠壓一(yi)(yi)(yi)層(ceng)(ceng)(ceng)(ceng)(ceng)鉛(qian)管(guan)。