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長(chang)途對(dui)稱通(tong)信(xin)(xin)電纜(lan)由不同數量和(he)不同絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)結(jie)構(gou)的四(si)線組構(gou)成。四(si)線組的常用(yong)形式為(wei)星絞組，也有的采用(yong)復(fu)對(dui)絞形式（圖2）。絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)有紙(zhi)(zhi)帶(dai)(dai)絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)、紙(zhi)(zhi)-繩(sheng)（紙(zhi)(zhi)帶(dai)(dai)和(he)紙(zhi)(zhi)繩(sheng)）絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)、聚(ju)(ju)(ju)乙烯(xi)(xi)繩(sheng)-帶(dai)(dai)絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)、聚(ju)(ju)(ju)苯乙烯(xi)(xi)繩(sheng)－帶(dai)(dai)絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)和(he)泡沫(mo)聚(ju)(ju)(ju)乙烯(xi)(xi)絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)等多(duo)種。高頻長(chang)途對(dui)稱通(tong)信(xin)(xin)電纜(lan)傳(chuan)輸頻率高，所以(yi)對(dui)電纜(lan)的結(jie)構(gou)性能要求較高。一般采用(yong)繩(sheng)－帶(dai)(dai)絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)的星絞四(si)線組結(jie)構(gou)。絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)材料常用(yong)聚(ju)(ju)(ju)苯乙烯(xi)(xi)、聚(ju)(ju)(ju)乙烯(xi)(xi)。紙(zhi)(zhi)帶(dai)(dai)紙(zhi)(zhi)繩(sheng)絕(jue)(jue)(jue)(jue)(jue)(jue)緣(yuan)(yuan)(yuan)(yuan)一般用(yong)于252千(qian)赫以(yi)下(xia)的低(di)頻對(dui)稱通(tong)信(xin)(xin)電纜(lan)。

電(dian)(dian)(dian)(dian)話電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)是(shi)用(yong)于市(shi)內、近郊和(he)工礦(kuang)企業等(deng)較小(xiao)范圍的(de)(de)區(qu)域電(dian)(dian)(dian)(dian)話連接的(de)(de)對(dui)(dui)(dui)(dui)稱通(tong)(tong)信電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)，常稱市(shi)內電(dian)(dian)(dian)(dian)話電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)。其(qi)主要特點為(wei)(wei)對(dui)(dui)(dui)(dui)數(shu)多(duo)（最多(duo)可達數(shu)千對(dui)(dui)(dui)(dui)，一(yi)(yi)般(ban)(ban)為(wei)(wei)數(shu)百或(huo)數(shu)十對(dui)(dui)(dui)(dui)）。由(you)于使用(yong)頻率低，通(tong)(tong)信距離近，因此線(xian)(xian)(xian)(xian)(xian)(xian)徑較長途通(tong)(tong)信電(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)話電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)的(de)(de)線(xian)(xian)(xian)(xian)(xian)(xian)組(zu)結構(gou)有對(dui)(dui)(dui)(dui)絞(jiao)(jiao)組(zu)、星(xing)絞(jiao)(jiao)組(zu)和(he)復(fu)對(dui)(dui)(dui)(dui)絞(jiao)(jiao)組(zu)3種(zhong)。按其(qi)線(xian)(xian)(xian)(xian)(xian)(xian)心(xin)絕(jue)(jue)緣(yuan)(yuan)(yuan)和(he)護層材(cai)料可分為(wei)(wei)紙絕(jue)(jue)緣(yuan)(yuan)(yuan)鉛(qian)護套電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)、聚(ju)乙(yi)烯(xi)絕(jue)(jue)緣(yuan)(yuan)(yuan)組(zu)合護層電(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(quan)塑電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)等(deng)。　電(dian)(dian)(dian)(dian)話電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)中(zhong)二根絕(jue)(jue)緣(yuan)(yuan)(yuan)導(dao)線(xian)(xian)(xian)(xian)(xian)(xian)心(xin)按一(yi)(yi)定節(jie)(jie)距絞(jiao)(jiao)合成(cheng)對(dui)(dui)(dui)(dui)構(gou)成(cheng)一(yi)(yi)個(ge)(ge)絕(jue)(jue)緣(yuan)(yuan)(yuan)線(xian)(xian)(xian)(xian)(xian)(xian)對(dui)(dui)(dui)(dui)。線(xian)(xian)(xian)(xian)(xian)(xian)對(dui)(dui)(dui)(dui)中(zhong)二根絕(jue)(jue)緣(yuan)(yuan)(yuan)導(dao)線(xian)(xian)(xian)(xian)(xian)(xian)心(xin)的(de)(de)顏色(se)不同（一(yi)(yi)般(ban)(ban)為(wei)(wei)紅色(se)和(he)白色(se)），以便(bian)接線(xian)(xian)(xian)(xian)(xian)(xian)時(shi)區(qu)分。電(dian)(dian)(dian)(dian)話電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)的(de)(de)纜(lan)(lan)(lan)(lan)心(xin)結構(gou)一(yi)(yi)般(ban)(ban)分為(wei)(wei)同心(xin)式(shi)和(he)單位式(shi)兩種(zhong)（圖3）。同一(yi)(yi)層中(zhong)相鄰線(xian)(xian)(xian)(xian)(xian)(xian)對(dui)(dui)(dui)(dui)的(de)(de)絞(jiao)(jiao)合節(jie)(jie)距應不相同，以減(jian)小(xiao)通(tong)(tong)話時(shi)的(de)(de)相互影響。在(zai)每一(yi)(yi)層中(zhong)都設有一(yi)(yi)個(ge)(ge)標志對(dui)(dui)(dui)(dui)（分別(bie)為(wei)(wei)藍色(se)和(he)白色(se)），便(bian)于接線(xian)(xian)(xian)(xian)(xian)(xian)時(shi)辨(bian)認。在(zai)80對(dui)(dui)(dui)(dui)以上的(de)(de)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)中(zhong)往往置(zhi)有預(yu)備線(xian)(xian)(xian)(xian)(xian)(xian)對(dui)(dui)(dui)(dui)以替(ti)換(huan)不合格線(xian)(xian)(xian)(xian)(xian)(xian)對(dui)(dui)(dui)(dui)。單位式(shi)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)以50對(dui)(dui)(dui)(dui)或(huo)100對(dui)(dui)(dui)(dui)及(ji)相應的(de)(de)預(yu)備對(dui)(dui)(dui)(dui)絞(jiao)(jiao)合成(cheng)一(yi)(yi)個(ge)(ge)基本(ben)單位，再由(you)若(ruo)干個(ge)(ge)基本(ben)單位絞(jiao)(jiao)合成(cheng)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)心(xin)。經(jing)干燥(zao)后擠壓上護套制成(cheng)電(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)（見圖）。

架(jia)空敷(fu)設(she)的(de)電(dian)話(hua)電(dian)纜(lan)需用自承(cheng)式，由鋼索承(cheng)受整個電(dian)纜(lan)的(de)重力。20世紀(ji)60年代(dai)以來，研制出(chu)在塑(su)料電(dian)纜(lan)中填充油(you)膏以防止潮氣和(he)水分的(de)防水型電(dian)纜(lan)。

為了提高通信電纜(lan)的防(fang)潮(chao)性(xing)、穩定性(xing)，20世(shi)紀70年(nian)代以來，在市(shi)內(nei)電話電纜(lan)中廣泛采用綜(zong)合(he)型電纜(lan)護層(ceng)(ceng)。其基本類型有3種。①Alpeth：纜(lan)心(xin)外(wai)擠(ji)壓(ya)一(yi)層(ceng)(ceng)聚(ju)(ju)乙(yi)烯(xi)護層(ceng)(ceng)，再(zai)搭接地縱(zong)向包裹0.2毫米皺紋鋁帶(dai)(dai)，充以聚(ju)(ju)異丁烯(xi)絕緣復合(he)物(wu)后外(wai)敷(fu)一(yi)層(ceng)(ceng)熱塑性(xing)膠粘(zhan)層(ceng)(ceng)，最(zui)(zui)外(wai)面擠(ji)壓(ya)一(yi)層(ceng)(ceng)聚(ju)(ju)乙(yi)烯(xi)護套。②Stalpeth：皺紋鋁帶(dai)(dai)外(wai)縱(zong)包一(yi)層(ceng)(ceng)皺紋鋼帶(dai)(dai)，外(wai)覆(fu)一(yi)層(ceng)(ceng)熱塑性(xing)材料(liao)，最(zui)(zui)外(wai)層(ceng)(ceng)再(zai)擠(ji)壓(ya)一(yi)層(ceng)(ceng)聚(ju)(ju)乙(yi)烯(xi)護套。③Lepeth：纜(lan)心(xin)上包覆(fu)一(yi)層(ceng)(ceng)聚(ju)(ju)乙(yi)烯(xi)護套，其外(wai)敷(fu)一(yi)層(ceng)(ceng)粘(zhan)性(xing)熱塑性(xing)材料(liao)，最(zui)(zui)外(wai)面擠(ji)壓(ya)一(yi)層(ceng)(ceng)鉛管。