電話[英語:Telephone,出自希臘(la)語τ?λε(tēle,意為“遠”)和(he)φων?(phōnē,意為“聲(sheng)音(yin)(yin)”),舊譯德(de)律風]是一種(zhong)可以(yi)傳(chuan)(chuan)送與接收聲(sheng)音(yin)(yin)的(de)遠程(cheng)通信設備。早在18世紀歐洲已有(you)“電話”一詞(ci),用來指用線串(chuan)成的(de)話筒(以(yi)線串(chuan)起杯子)。電話的(de)出現要(yao)歸功于(yu)亞(ya)歷山大·格拉漢姆·貝爾,早期電話機的(de)原理為:說話聲(sheng)音(yin)(yin)為空氣里的(de)復(fu)合(he)振動,可傳(chuan)(chuan)輸(shu)到固體上(shang),通過(guo)電脈沖于(yu)導電金屬上(shang)傳(chuan)(chuan)遞。貝爾于(yu)1876年3月申請了電話的(de)專利權(quan)。
美國國會(hui)2002年(nian)6月15日269號決議(yi)確認安東尼奧(ao)·穆(mu)齊(qi)(qi)為電話的(de)發明(ming)人。穆(mu)齊(qi)(qi)于(yu)1860年(nian)首次向公眾展示了(le)他的(de)發明(ming),并(bing)在紐約的(de)意(yi)大(da)利語報紙上發表了(le)關于(yu)這項發明(ming)的(de)介紹。
歷(li)史上對電(dian)(dian)(dian)(dian)話(hua)(hua)的改進和發明包(bao)括(kuo):碳粉(fen)話(hua)(hua)筒、人工交換板、撥號(hao)盤、自動電(dian)(dian)(dian)(dian)話(hua)(hua)交換機、程控電(dian)(dian)(dian)(dian)話(hua)(hua)交換機、雙音(yin)多(duo)頻撥號(hao)、語(yu)音(yin)數(shu)字采樣等(deng)。近年來的新技術包(bao)括(kuo):ISDN、DSL、網絡電(dian)(dian)(dian)(dian)話(hua)(hua)、模擬移動電(dian)(dian)(dian)(dian)話(hua)(hua)和數(shu)字移動電(dian)(dian)(dian)(dian)話(hua)(hua)等(deng)。
這(zhe)一行業(ye)通常(chang)分為電話(hua)(hua)設備制造商和電話(hua)(hua)網絡運(yun)營商。在(zai)歷史上,網絡運(yun)營商通常(chang)都擁有全(quan)國性(xing)的(de)壟斷。近年來(lai),隨著全(quan)球電信市(shi)場的(de)開放和集成(cheng)以及技術的(de)發展,逐(zhu)漸出現(xian)多家運(yun)營商在(zai)同一市(shi)場競爭的(de)局(ju)面(mian)。例如,貝(bei)爾(er)系統,即AT&T的(de)下屬(shu)公司(si)曾(ceng)擁有美國電話(hua)(hua)市(shi)場的(de)80%。1984年,由(you)于美國司(si)法部反壟斷訴訟,貝(bei)爾(er)系統被迫分區(qu)成(cheng)多個(ge)獨立的(de)地方貝(bei)爾(er)公司(si)。有一個(ge)說(shuo)法可以說(shuo)明這(zhe)個(ge)現(xian)象:在(zai)AT&T未分區(qu)前(qian),IBM是美國第(di)二大公司(si)。在(zai)AT&T分區(qu)成(cheng)七個(ge)公司(si)后(hou),IBM的(de)排(pai)名變(bian)成(cheng)第(di)八(ba)名。
電(dian)(dian)話機是(shi)通過電(dian)(dian)信號雙向傳輸(shu)話音的終端(duan)設備。
歷史上對電(dian)話(hua)機的改進(jin)和發明包(bao)(bao)括:碳粉(fen)話(hua)筒、電(dian)話(hua)人(ren)工交換(huan)板、撥號(hao)盤、自動(dong)(dong)電(dian)話(hua)交換(huan)機、程(cheng)控(kong)電(dian)話(hua)交換(huan)機、雙音多頻撥號(hao)、語音數(shu)字采(cai)樣(yang)等(deng)。新(xin)技術包(bao)(bao)括:ISDN、DSL、模擬移(yi)動(dong)(dong)電(dian)話(hua)和數(shu)字移(yi)動(dong)(dong)電(dian)話(hua)機等(deng)。
電(dian)話電(dian)源(yuan)線、電(dian)話線、收線開(kai)關(guan)、受話器、增音按鈕、送話器、本機號碼(ma)片(pian)、鈴(ling)聲及(ji)免(mian)提(ti)喇叭(ba)、記憶代碼(ma)鍵(jian)(jian)(jian)、記憶號碼(ma)片(pian)、數(shu)字按鍵(jian)(jian)(jian)、記憶取出鍵(jian)(jian)(jian)、記憶儲存(cun)鍵(jian)(jian)(jian)、重撥鍵(jian)(jian)(jian)、工作指示(shi)燈、免(mian)提(ti)鍵(jian)(jian)(jian)、R鍵(jian)(jian)(jian)、免(mian)提(ti)送話器、鈴(ling)聲調節(jie)開(kai)關(guan)、P/T開(kai)關(guan)、免(mian)提(ti)接收音量調節(jie)旋鈕。
電話通(tong)信是通(tong)過聲能(neng)與電能(neng)相互轉換、并利用“電”這個(ge)媒(mei)介來傳輸語言的一(yi)種(zhong)通(tong)信技術。兩個(ge)用戶要進行通(tong)信,最簡單的形(xing)式就是將兩部電話機(ji)用一(yi)對線路連接(jie)起來。
當發話者(zhe)拿起電話機對著送話器講話時,聲(sheng)帶的振動激勵(li)空氣(qi)振動,形成聲(sheng)波。
聲波作用于送話器上,使之(zhi)產生電流,稱(cheng)為話音電流。
話音電流沿著線路傳送到(dao)對方電話機(ji)的受話器內。
而受(shou)話器(qi)作用與送話器(qi)剛好相反——把電流轉化為聲波,通過空氣傳至人(ren)的耳朵中(zhong)。
這樣,就完(wan)成了最簡(jian)單的通話過程(cheng)。
電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)是美國人A.G.貝(bei)爾于(yu)1876年(nian)(nian)發(fa)明的(de)(de)。他用兩(liang)根導線連接(jie)兩(liang)個結構完全(quan)(quan)相同、在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁鐵上裝有(you)振動膜片(pian)的(de)(de)送(song)話(hua)(hua)(hua)(hua)(hua)器(qi)和受話(hua)(hua)(hua)(hua)(hua)器(qi),首(shou)先(xian)實現(xian)(xian)(xian)兩(liang)端(duan)通(tong)話(hua)(hua)(hua)(hua)(hua)。但(dan)通(tong)話(hua)(hua)(hua)(hua)(hua)距離(li)短、效(xiao)率低。1878年(nian)(nian)出(chu)(chu)現(xian)(xian)(xian)了(le)(le)炭精送(song)話(hua)(hua)(hua)(hua)(hua)器(qi),使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)送(song)話(hua)(hua)(hua)(hua)(hua)器(qi)效(xiao)率大大提(ti)高(gao)。受話(hua)(hua)(hua)(hua)(hua)器(qi)結構也(ye)有(you)改(gai)進。最早的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)是磁石電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji),靠自(zi)備電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian),用手(shou)搖發(fa)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)發(fa)送(song)呼叫信號(hao)。1880年(nian)(nian)出(chu)(chu)現(xian)(xian)(xian)共電(dian)(dian)(dian)(dian)(dian)(dian)(dian)式電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji),改(gai)由共電(dian)(dian)(dian)(dian)(dian)(dian)(dian)交(jiao)換(huan)機(ji)(ji)(ji)(ji)集(ji)(ji)中供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian),省去手(shou)播發(fa)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)和干(gan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)。1891年(nian)(nian)出(chu)(chu)現(xian)(xian)(xian)了(le)(le)旋轉撥(bo)號(hao)盤式自(zi)動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji),它可(ke)以發(fa)出(chu)(chu)直流撥(bo)號(hao)脈沖,控(kong)制自(zi)動交(jiao)換(huan)機(ji)(ji)(ji)(ji)動作,選擇被(bei)叫用戶,自(zi)動完成(cheng)(cheng)交(jiao)換(huan)功(gong)能。從而把電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)通(tong)信推向(xiang)一(yi)個新階段。到20世紀60年(nian)(nian)代末期出(chu)(chu)現(xian)(xian)(xian)了(le)(le)按鍵(jian)式全(quan)(quan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)。除脈沖發(fa)號(hao)方式外,又出(chu)(chu)現(xian)(xian)(xian)了(le)(le)雙音(yin)(yin)多頻(pin)(DTMF)發(fa)號(hao)方式。隨(sui)著(zhu)程控(kong)交(jiao)換(huan)機(ji)(ji)(ji)(ji)的(de)(de)發(fa)展,雙音(yin)(yin)頻(pin)按鍵(jian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)已(yi)(yi)逐步普及(ji)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)正在(zai)向(xiang)集(ji)(ji)成(cheng)(cheng)化(hua)邁進,話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)專(zhuan)用集(ji)(ji)成(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)已(yi)(yi)廣泛用于(yu)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)各組成(cheng)(cheng)部分。各種(zhong)多功(gong)能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)和特種(zhong)用途電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)也(ye)應(ying)運而生。到20世紀90年(nian)(nian)代初,已(yi)(yi)有(you)了(le)(le)將撥(bo)號(hao)、通(tong)話(hua)(hua)(hua)(hua)(hua)、振鈴三種(zhong)功(gong)能集(ji)(ji)于(yu)一(yi)塊集(ji)(ji)成(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)上的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)。隨(sui)著(zhu)話(hua)(hua)(hua)(hua)(hua)音(yin)(yin)識(shi)別技術的(de)(de)發(fa)展,直接(jie)用話(hua)(hua)(hua)(hua)(hua)音(yin)(yin)“撥(bo)號(hao)”的(de)(de)新型(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)也(ye)正在(zai)出(chu)(chu)現(xian)(xian)(xian)。
最初的電(dian)(dian)(dian)(dian)話(hua)機(終端(duan))是由(you)微型發電(dian)(dian)(dian)(dian)機和電(dian)(dian)(dian)(dian)池構成的磁(ci)石(shi)式電(dian)(dian)(dian)(dian)話(hua)機,打電(dian)(dian)(dian)(dian)話(hua)時,使用者用手(shou)搖微型發電(dian)(dian)(dian)(dian)機發出(chu)電(dian)(dian)(dian)(dian)信號(hao)呼叫對(dui)方(fang),對(dui)方(fang)啟(qi)機后(hou)構成通話(hua)回路。后(hou)來,1877年愛(ai)迪生(sheng)(T.E.Edison)發明(ming)了(le)(le)(le)碳素(su)送(song)話(hua)器和誘導(dao)線路后(hou)通話(hua)距(ju)離延長了(le)(le)(le)。同一年又發明(ming)了(le)(le)(le)共電(dian)(dian)(dian)(dian)式電(dian)(dian)(dian)(dian)話(hua)機。1891年終于發展(zhan)到(dao)A.B.Strowger發明(ming)了(le)(le)(le)自動(dong)式電(dian)(dian)(dian)(dian)話(hua)機。
電(dian)話(hua)機設(she)置(zhi)在電(dian)話(hua)通信(xin)起點和終(zhong)點的(de)(de)(de)用(yong)戶(hu)側,是電(dian)話(hua)網的(de)(de)(de)用(yong)戶(hu)終(zhong)端設(she)備。現代的(de)(de)(de)電(dian)話(hua)機能夠方(fang)便地實現終(zhong)端用(yong)戶(hu)之間的(de)(de)(de)呼(hu)叫(jiao)和通話(hua),是經過一百多年來許多人的(de)(de)(de)研究和無(wu)數次(ci)的(de)(de)(de)改進而形成的(de)(de)(de)。盡管它(ta)們的(de)(de)(de)式(shi)樣千差(cha)萬(wan)別,但一般都(dou)有如下(xia)基本功(gong)能:
1、聲電互換
因為要進行(xing)快速的(de)、遠距離的(de)通信,不能直接傳(chuan)送聲音,而必須先(xian)把聲音變成電信號(hao)(即以電作為載(zai)體),到對方后再把電信號(hao)還原成為聲音。
2、摘機識別
當主叫方(fang)拿(na)起電話機時,交(jiao)換機應有能(neng)知道“有人要(yao)打電話”的功(gong)能(neng),以(yi)便交(jiao)換機做好接續準備。
3、發送信號
自(zi)動電話機正是通過發送撥號(hao)(hao)信號(hao)(hao)來指揮電話交換機的工(gong)作,并進而建(jian)立兩個電話機之間的連接(jie)的。
4、響鈴
即在對(dui)方(fang)來(lai)電話時,電話機(ji)能以鈴聲告訴主人(ren):“有人(ren)來(lai)電話了。”
5、電接續
電話(hua)機中,實現這五大功能的部件依次是:送(song)受話(hua)器、叉(cha)簧、撥號(hao)盤(pan)(或按(an)鍵盤(pan))、電話(hua)鈴和電話(hua)回(hui)路(lu)。
電(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)機具有將終(zhong)端(duan)的(de)(de)(de)(de)音(yin)(yin)波轉(zhuan)換為(wei)電(dian)(dian)(dian)(dian)(dian)(dian)子信號,通過電(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)線傳(chuan)送(song)(song)到遠距離的(de)(de)(de)(de)對(dui)方(fang),同時將對(dui)方(fang)傳(chuan)送(song)(song)來的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)子信號再生為(wei)語(yu)音(yin)(yin)(音(yin)(yin)波),使其(qi)通話(hua)(hua)(hua)的(de)(de)(de)(de)功(gong)能(neng),以及發(fa)(fa)送(song)(song)可從(cong)多個對(dui)方(fang)中(zhong)選擇(ze)的(de)(de)(de)(de)信號(撥號脈沖),告(gao)知對(dui)方(fang)的(de)(de)(de)(de)呼(hu)叫音(yin)(yin)等功(gong)能(neng)。電(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)機由將語(yu)音(yin)(yin)轉(zhuan)換為(wei)電(dian)(dian)(dian)(dian)(dian)(dian)流發(fa)(fa)送(song)(song)到電(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)線的(de)(de)(de)(de)送(song)(song)話(hua)(hua)(hua)機、將對(dui)方(fang)傳(chuan)送(song)(song)來的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流還原為(wei)語(yu)音(yin)(yin)的(de)(de)(de)(de)受話(hua)(hua)(hua)機、呼(hu)叫對(dui)方(fang)的(de)(de)(de)(de)撥號或按鈕(niu)、發(fa)(fa)送(song)(song)呼(hu)叫音(yin)(yin)的(de)(de)(de)(de)鈴(ling)聲(sheng)、將這些連接(jie)在電(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)線上執(zhi)行(xing)其(qi)功(gong)能(neng)的(de)(de)(de)(de)線路網等組成。送(song)(song)話(hua)(hua)(hua)機內有裝滿碳素(su)顆(ke)粒的(de)(de)(de)(de)小箱子,其(qi)前方(fang)有薄硬鋁(lv)合金振(zhen)(zhen)動(dong)板。振(zhen)(zhen)動(dong)板根據語(yu)音(yin)(yin)振(zhen)(zhen)動(dong),振(zhen)(zhen)動(dong)碳素(su)顆(ke)粒,碳素(su)顆(ke)粒傳(chuan)導電(dian)(dian)(dian)(dian)(dian)(dian)流,隨著顆(ke)粒的(de)(de)(de)(de)接(jie)觸程度,電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)發(fa)(fa)生變化,生成語(yu)音(yin)(yin)電(dian)(dian)(dian)(dian)(dian)(dian)流。受話(hua)(hua)(hua)機接(jie)受對(dui)方(fang)的(de)(de)(de)(de)語(yu)音(yin)(yin)電(dian)(dian)(dian)(dian)(dian)(dian)流后,在線圈上生成語(yu)音(yin)(yin)電(dian)(dian)(dian)(dian)(dian)(dian)流引起的(de)(de)(de)(de)磁力,振(zhen)(zhen)動(dong)鐵振(zhen)(zhen)動(dong)板,發(fa)(fa)出聲(sheng)音(yin)(yin)。
無(wu)線環路-無(wu)繩電(dian)話
電話子母機
數字無繩電話
模擬無繩電話
移動電話手機
小靈(ling)通(無(wu)線電話)
隨(sui)著IT技術的(de)不斷的(de)飛速發展,嵌入式終端設備的(de)處理能力越(yue)來越(yue)強,21世紀初出現了一種(zhong)帶個(ge)人數據助(zhu)理(PDA)的(de)電(dian)話機“智能電(dian)話”。
智能(neng)(neng)(neng)電(dian)(dian)話(hua)除了有完整的(de)(de)固定電(dian)(dian)話(hua)功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng)外,通常還(huan)具有大容量的(de)(de)名(ming)片(pian)管理功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng)、來去電(dian)(dian)管理功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng)、防(fang)止(zhi)電(dian)(dian)話(hua)騷擾(電(dian)(dian)話(hua)防(fang)火墻)功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng)、企業集團電(dian)(dian)話(hua)名(ming)片(pian)(內(nei)部名(ming)片(pian))管理功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng),以及輔助辦公的(de)(de)許多功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng),比(bi)如:日程(cheng)安排、便箋、日歷、計算器等功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng)。早期的(de)(de)智能(neng)(neng)(neng)電(dian)(dian)話(hua)通過撥號上網(wang),具有一定的(de)(de)信息交換能(neng)(neng)(neng)力(li),實(shi)現(xian)了發送短信、接(jie)收文字信息的(de)(de)功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng)。隨著固網(wang)智能(neng)(neng)(neng)電(dian)(dian)話(hua)在中(zhong)國近十年的(de)(de)發展,其(qi)處(chu)理能(neng)(neng)(neng)力(li)加強,逐漸地增加了智能(neng)(neng)(neng)手機(Smartphone)具有的(de)(de)功(gong)(gong)(gong)(gong)(gong)能(neng)(neng)(neng)。
智能(neng)(neng)(neng)電(dian)(dian)話已有(you)通過(guo)因特網(wang)上網(wang)的(de)能(neng)(neng)(neng)力及較(jiao)強的(de)多(duo)媒(mei)的(de)體功(gong)(gong)能(neng)(neng)(neng)。可以(yi)進(jin)行網(wang)絡瀏覽、音視頻的(de)播放、具有(you)電(dian)(dian)子書、電(dian)(dian)子相框(kuang)等功(gong)(gong)能(neng)(neng)(neng)。同(tong)時智能(neng)(neng)(neng)電(dian)(dian)話在(zai)輔助(zhu)辦公(gong)、輔助(zhu)營銷、娛樂等方(fang)面(mian)的(de)功(gong)(gong)能(neng)(neng)(neng)也有(you)了(le)大(da)(da)大(da)(da)的(de)加強。在(zai)對傳統固(gu)定電(dian)(dian)話顛(dian)覆的(de)基礎上,實現(xian)了(le)更多(duo)的(de)商(shang)務功(gong)(gong)能(neng)(neng)(neng)和PDA功(gong)(gong)能(neng)(neng)(neng)。
環境溫度(du):-10℃~40℃
相對濕度:45%~95%
大氣壓力:860~1060mbar
環(huan)境(jing)噪(zao)聲(sheng):≤60dB(A)
1、工作頻率:300~3400HZ
2、脈(mo)沖(chong)通斷比:1.6±0.2∶1
3、雙音(yin)頻撥號(hao)頻偏:≤±1.5%
4、雙音頻(pin)(pin)信(xin)號電(dian)平(ping):①低(di)頻(pin)(pin)群:-9±3dB;②高頻(pin)(pin)群:-7±3dB;③頻(pin)(pin)率組合(he)中高頻(pin)(pin)分量比(bi)低(di)頻(pin)(pin)分量高2±1dB
5、振鈴聲級:≥70dB(A)
6、電聲性能:
①在(zai)0公里(li)(li)時(shi),客觀發送參(can)(can)考當量≥+3;在(zai)3公里(li)(li)時(shi),客觀發送參(can)(can)考當量≤+15;在(zai)5公里(li)(li)時(shi),客觀發送參(can)(can)考當量≤+15。
②在(zai)0公里(li)(li)時(shi)(shi),客觀接收參考(kao)當量≥-5;在(zai)3公里(li)(li)時(shi)(shi),客觀接收參考(kao)當量≤+2;在(zai)5公里(li)(li)時(shi)(shi),客觀接收摻考(kao)當量≤+2。
③在0公(gong)里時(shi),客(ke)觀(guan)側音參考(kao)當(dang)(dang)量≥+3;在3公(gong)里時(shi),客(ke)觀(guan)側音參考(kao)當(dang)(dang)量≥+10;在5公(gong)里時(shi),客(ke)觀(guan)側音參考(kao)當(dang)(dang)量≥+10。
高科技電(dian)(dian)(dian)話(hua)(hua)機(ji)的(de)(de)(de)(de)發(fa)(fa)展都(dou)是隨著無線通(tong)信(xin)的(de)(de)(de)(de)發(fa)(fa)達而形成的(de)(de)(de)(de)。電(dian)(dian)(dian)話(hua)(hua)機(ji)的(de)(de)(de)(de)發(fa)(fa)展趨勢(shi)經過Digital電(dian)(dian)(dian)話(hua)(hua)機(ji)和(he)PCS后(hou)發(fa)(fa)展到(dao)(dao)可以(yi)用衛(wei)星通(tong)信(xin)的(de)(de)(de)(de)IMT-200服務。IMT-200支持信(xin)息的(de)(de)(de)(de)高速(su)傳(chuan)送,Packet,畫像(xiang)等(deng)多媒體的(de)(de)(de)(de)服務,將(jiang)來(lai)世界各個地方都(dou)可以(yi)使用所(suo)有聲(sheng)音電(dian)(dian)(dian)話(hua)(hua),電(dian)(dian)(dian)報用戶直通(tong)電(dian)(dian)(dian)路(lu),傳(chuan)呼和(he)電(dian)(dian)(dian)子(zi)郵(you)件;隨著電(dian)(dian)(dian)子(zi)郵(you)件的(de)(de)(de)(de)普及,網絡也日益化,網絡電(dian)(dian)(dian)話(hua)(hua)已(yi)是不(bu)可阻擋的(de)(de)(de)(de)發(fa)(fa)展趨勢(shi)。現有的(de)(de)(de)(de)固定(ding)電(dian)(dian)(dian)話(hua)(hua),已(yi)經不(bu)能(neng)提供人們的(de)(de)(de)(de)需要了(le)。未(wei)來(lai)的(de)(de)(de)(de)固定(ding)電(dian)(dian)(dian)話(hua)(hua)講裝備(bei)攝像(xiang)頭,帶有色彩的(de)(de)(de)(de)液晶顯示(shi)器,我們在接固定(ding)電(dian)(dian)(dian)話(hua)(hua)的(de)(de)(de)(de)時候,都(dou)能(neng)夠看到(dao)(dao)雙方。