電話(hua)[英語(yu):Telephone,出(chu)自希臘語(yu)τ?λε(tēle,意(yi)為“遠(yuan)”)和φων?(phōnē,意(yi)為“聲音”),舊(jiu)譯德律風(feng)]是一種(zhong)可(ke)以傳送與接收聲音的(de)遠(yuan)程(cheng)通信設備。早在(zai)18世紀歐洲已(yi)有“電話(hua)”一詞,用(yong)來指用(yong)線串(chuan)成的(de)話(hua)筒(以線串(chuan)起杯子)。電話(hua)的(de)出(chu)現(xian)要歸功于(yu)亞歷山大(da)·格(ge)拉漢(han)姆(mu)·貝(bei)爾(er),早期電話(hua)機的(de)原(yuan)理為:說話(hua)聲音為空氣里(li)的(de)復合振動(dong),可(ke)傳輸(shu)到固體上,通過電脈沖于(yu)導電金屬上傳遞。貝(bei)爾(er)于(yu)1876年3月申請了電話(hua)的(de)專(zhuan)利權。
美國(guo)國(guo)會2002年6月15日(ri)269號決議確認安東尼奧·穆齊(qi)為(wei)電話(hua)的發明(ming)(ming)人。穆齊(qi)于(yu)(yu)1860年首次向公眾展示了他的發明(ming)(ming),并在紐約的意大利語報紙上(shang)發表了關于(yu)(yu)這(zhe)項(xiang)發明(ming)(ming)的介紹。
歷(li)史(shi)上對電話的改進和(he)發明包(bao)括(kuo)(kuo):碳粉(fen)話筒、人(ren)工(gong)交(jiao)換板、撥號(hao)盤(pan)、自動電話交(jiao)換機、程控電話交(jiao)換機、雙(shuang)音多頻撥號(hao)、語音數字(zi)采樣等。近年來的新技術包(bao)括(kuo)(kuo):ISDN、DSL、網絡電話、模擬移動電話和(he)數字(zi)移動電話等。
這一行(xing)業通常(chang)(chang)分為(wei)電(dian)話設備(bei)制造商和電(dian)話網(wang)絡(luo)運(yun)營(ying)商。在歷史上,網(wang)絡(luo)運(yun)營(ying)商通常(chang)(chang)都擁有(you)全國(guo)性的(de)(de)壟斷。近年來,隨著全球電(dian)信市(shi)(shi)場(chang)的(de)(de)開放和集(ji)成以及技術的(de)(de)發(fa)展,逐漸出現多(duo)家(jia)運(yun)營(ying)商在同一市(shi)(shi)場(chang)競(jing)爭(zheng)的(de)(de)局面。例如,貝爾系統,即AT&T的(de)(de)下屬公司曾擁有(you)美國(guo)電(dian)話市(shi)(shi)場(chang)的(de)(de)80%。1984年,由于(yu)美國(guo)司法部反(fan)壟斷訴訟(song),貝爾系統被迫分區(qu)成多(duo)個(ge)獨立的(de)(de)地(di)方貝爾公司。有(you)一個(ge)說法可(ke)以說明(ming)這個(ge)現象(xiang):在AT&T未(wei)分區(qu)前,IBM是美國(guo)第二大公司。在AT&T分區(qu)成七(qi)個(ge)公司后,IBM的(de)(de)排(pai)名(ming)變成第八名(ming)。
電話機是通(tong)過電信號雙向傳輸(shu)話音的終端設備。
歷史(shi)上對電(dian)話(hua)機的改進(jin)和(he)發明包括:碳粉話(hua)筒、電(dian)話(hua)人工交換板、撥(bo)(bo)號盤、自(zi)動電(dian)話(hua)交換機、程控電(dian)話(hua)交換機、雙音多頻撥(bo)(bo)號、語音數(shu)字(zi)采樣(yang)等。新技(ji)術包括:ISDN、DSL、模(mo)擬移動電(dian)話(hua)和(he)數(shu)字(zi)移動電(dian)話(hua)機等。
電(dian)(dian)話(hua)電(dian)(dian)源線(xian)、電(dian)(dian)話(hua)線(xian)、收線(xian)開關、受(shou)話(hua)器、增音(yin)按(an)鈕(niu)、送話(hua)器、本(ben)機號(hao)碼片、鈴聲及免提喇叭、記憶代(dai)碼鍵(jian)(jian)、記憶號(hao)碼片、數字(zi)按(an)鍵(jian)(jian)、記憶取出鍵(jian)(jian)、記憶儲存(cun)鍵(jian)(jian)、重撥鍵(jian)(jian)、工(gong)作指示燈、免提鍵(jian)(jian)、R鍵(jian)(jian)、免提送話(hua)器、鈴聲調(diao)節開關、P/T開關、免提接收音(yin)量(liang)調(diao)節旋鈕(niu)。
電(dian)(dian)話(hua)通信(xin)是通過聲能與電(dian)(dian)能相互轉換、并利用(yong)“電(dian)(dian)”這個媒介來(lai)傳輸語言的(de)一(yi)(yi)種通信(xin)技(ji)術(shu)。兩個用(yong)戶要進行通信(xin),最(zui)簡(jian)單的(de)形式就是將兩部電(dian)(dian)話(hua)機(ji)用(yong)一(yi)(yi)對(dui)線路連(lian)接(jie)起來(lai)。
當發(fa)話(hua)者拿起電話(hua)機(ji)對著送話(hua)器講話(hua)時,聲帶的振(zhen)動激勵空氣(qi)振(zhen)動,形成(cheng)聲波。
聲波作用于送話器(qi)上,使(shi)之產生電流,稱為話音電流。
話(hua)音電流沿(yan)著線(xian)路傳送到對方電話(hua)機的受話(hua)器內。
而受(shou)話器作(zuo)用與送話器剛好相(xiang)反(fan)——把電流轉化(hua)為聲波,通過空氣(qi)傳至人(ren)的耳朵中。
這(zhe)樣,就完成了(le)最簡單的通話(hua)過程。
電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)是(shi)美(mei)國人A.G.貝(bei)爾于(yu)(yu)1876年發(fa)(fa)(fa)(fa)(fa)明(ming)的(de)(de)。他用兩(liang)根導線(xian)連(lian)接兩(liang)個結構(gou)完全相同、在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)磁鐵上裝(zhuang)有(you)(you)振動(dong)膜片的(de)(de)送話(hua)(hua)(hua)(hua)器和(he)受(shou)話(hua)(hua)(hua)(hua)器,首先實現(xian)兩(liang)端通話(hua)(hua)(hua)(hua)。但通話(hua)(hua)(hua)(hua)距(ju)離短(duan)、效(xiao)率低。1878年出(chu)(chu)現(xian)了(le)(le)炭精(jing)送話(hua)(hua)(hua)(hua)器,使(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)送話(hua)(hua)(hua)(hua)器效(xiao)率大大提高。受(shou)話(hua)(hua)(hua)(hua)器結構(gou)也(ye)有(you)(you)改進(jin)。最早的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)是(shi)磁石電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji),靠自(zi)備電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),用手搖發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)發(fa)(fa)(fa)(fa)(fa)送呼(hu)叫信(xin)號(hao)。1880年出(chu)(chu)現(xian)共電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)式(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji),改由共電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)交(jiao)換機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)集(ji)中供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),省去手播(bo)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)和(he)干電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池。1891年出(chu)(chu)現(xian)了(le)(le)旋轉撥(bo)(bo)(bo)號(hao)盤(pan)式(shi)(shi)自(zi)動(dong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji),它(ta)可以發(fa)(fa)(fa)(fa)(fa)出(chu)(chu)直流撥(bo)(bo)(bo)號(hao)脈沖,控(kong)(kong)制(zhi)自(zi)動(dong)交(jiao)換機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)動(dong)作,選擇(ze)被(bei)叫用戶(hu),自(zi)動(dong)完成交(jiao)換功(gong)能。從而把電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)通信(xin)推(tui)向一個新(xin)階段。到(dao)20世(shi)(shi)紀60年代(dai)末期出(chu)(chu)現(xian)了(le)(le)按鍵(jian)式(shi)(shi)全電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)。除脈沖發(fa)(fa)(fa)(fa)(fa)號(hao)方(fang)式(shi)(shi)外,又出(chu)(chu)現(xian)了(le)(le)雙(shuang)音多(duo)頻(DTMF)發(fa)(fa)(fa)(fa)(fa)號(hao)方(fang)式(shi)(shi)。隨著程控(kong)(kong)交(jiao)換機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)的(de)(de)發(fa)(fa)(fa)(fa)(fa)展,雙(shuang)音頻按鍵(jian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)已(yi)(yi)逐步(bu)普及。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)正在向集(ji)成化邁(mai)進(jin),話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)專用集(ji)成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)已(yi)(yi)廣泛(fan)用于(yu)(yu)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)各(ge)組成部分(fen)。各(ge)種多(duo)功(gong)能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)和(he)特種用途電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)也(ye)應運而生。到(dao)20世(shi)(shi)紀90年代(dai)初,已(yi)(yi)有(you)(you)了(le)(le)將撥(bo)(bo)(bo)號(hao)、通話(hua)(hua)(hua)(hua)、振鈴三種功(gong)能集(ji)于(yu)(yu)一塊集(ji)成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)上的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)。隨著話(hua)(hua)(hua)(hua)音識別技(ji)術的(de)(de)發(fa)(fa)(fa)(fa)(fa)展,直接用話(hua)(hua)(hua)(hua)音“撥(bo)(bo)(bo)號(hao)”的(de)(de)新(xin)型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)話(hua)(hua)(hua)(hua)機(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)也(ye)正在出(chu)(chu)現(xian)。
最初的電話(hua)(hua)(hua)機(ji)(ji)(ji)(終(zhong)端)是(shi)由微型發(fa)(fa)電機(ji)(ji)(ji)和電池構成的磁石式(shi)(shi)電話(hua)(hua)(hua)機(ji)(ji)(ji),打電話(hua)(hua)(hua)時,使用者用手(shou)搖微型發(fa)(fa)電機(ji)(ji)(ji)發(fa)(fa)出(chu)電信號呼叫(jiao)對(dui)方(fang),對(dui)方(fang)啟(qi)機(ji)(ji)(ji)后(hou)構成通話(hua)(hua)(hua)回路。后(hou)來,1877年(nian)愛迪生(sheng)(T.E.Edison)發(fa)(fa)明了(le)碳素送話(hua)(hua)(hua)器和誘導線(xian)路后(hou)通話(hua)(hua)(hua)距離延長了(le)。同一年(nian)又發(fa)(fa)明了(le)共(gong)電式(shi)(shi)電話(hua)(hua)(hua)機(ji)(ji)(ji)。1891年(nian)終(zhong)于(yu)發(fa)(fa)展(zhan)到A.B.Strowger發(fa)(fa)明了(le)自動式(shi)(shi)電話(hua)(hua)(hua)機(ji)(ji)(ji)。
電(dian)話機設(she)置在電(dian)話通(tong)信起點和終點的(de)(de)用戶側,是(shi)電(dian)話網的(de)(de)用戶終端設(she)備。現代(dai)的(de)(de)電(dian)話機能夠(gou)方便(bian)地實現終端用戶之(zhi)間的(de)(de)呼叫和通(tong)話,是(shi)經過一(yi)百多(duo)年來許多(duo)人的(de)(de)研究(jiu)和無數次(ci)的(de)(de)改進而形成的(de)(de)。盡管它們的(de)(de)式樣千差萬(wan)別,但一(yi)般都有如下基本功能:
1、聲電互換
因(yin)為要進行(xing)快速的、遠距離的通(tong)信(xin),不(bu)能直接傳送聲(sheng)音(yin),而必須先(xian)把聲(sheng)音(yin)變成電(dian)信(xin)號(即以電(dian)作為載體),到對方后再(zai)把電(dian)信(xin)號還原成為聲(sheng)音(yin)。
2、摘機識別
當主叫方拿(na)起電(dian)話機(ji)時,交換機(ji)應有(you)能知道“有(you)人要打電(dian)話”的功能,以便(bian)交換機(ji)做好接續準(zhun)備。
3、發送信號
自動電(dian)話機(ji)正是通過發送撥號信號來指揮電(dian)話交換(huan)機(ji)的工作,并(bing)進而建立兩個電(dian)話機(ji)之間的連接(jie)的。
4、響鈴
即在對方來電話時,電話機能以鈴聲告訴主人:“有(you)人來電話了(le)。”
5、電接續
電(dian)話(hua)機(ji)中,實(shi)現這五(wu)大(da)功能的部件依次是:送(song)受話(hua)器、叉簧、撥(bo)號盤(pan)(或按鍵(jian)盤(pan))、電(dian)話(hua)鈴和電(dian)話(hua)回路。
電(dian)(dian)(dian)話(hua)機(ji)具有(you)將(jiang)終(zhong)端的(de)(de)(de)(de)(de)音(yin)波(bo)(bo)轉換為(wei)(wei)電(dian)(dian)(dian)子信號(hao),通過電(dian)(dian)(dian)話(hua)線(xian)傳(chuan)(chuan)送(song)到(dao)(dao)遠距離的(de)(de)(de)(de)(de)對(dui)方(fang),同時將(jiang)對(dui)方(fang)傳(chuan)(chuan)送(song)來的(de)(de)(de)(de)(de)電(dian)(dian)(dian)子信號(hao)再生(sheng)為(wei)(wei)語音(yin)(音(yin)波(bo)(bo)),使其通話(hua)的(de)(de)(de)(de)(de)功能,以及發送(song)可從(cong)多個對(dui)方(fang)中選擇的(de)(de)(de)(de)(de)信號(hao)(撥(bo)號(hao)脈沖(chong)),告(gao)知對(dui)方(fang)的(de)(de)(de)(de)(de)呼叫(jiao)音(yin)等功能。電(dian)(dian)(dian)話(hua)機(ji)由將(jiang)語音(yin)轉換為(wei)(wei)電(dian)(dian)(dian)流發送(song)到(dao)(dao)電(dian)(dian)(dian)話(hua)線(xian)的(de)(de)(de)(de)(de)送(song)話(hua)機(ji)、將(jiang)對(dui)方(fang)傳(chuan)(chuan)送(song)來的(de)(de)(de)(de)(de)電(dian)(dian)(dian)流還(huan)原為(wei)(wei)語音(yin)的(de)(de)(de)(de)(de)受話(hua)機(ji)、呼叫(jiao)對(dui)方(fang)的(de)(de)(de)(de)(de)撥(bo)號(hao)或按鈕、發送(song)呼叫(jiao)音(yin)的(de)(de)(de)(de)(de)鈴聲(sheng)、將(jiang)這些(xie)連接在電(dian)(dian)(dian)話(hua)線(xian)上(shang)執行其功能的(de)(de)(de)(de)(de)線(xian)路網(wang)等組成。送(song)話(hua)機(ji)內(nei)有(you)裝(zhuang)滿(man)碳素顆粒(li)(li)的(de)(de)(de)(de)(de)小箱子,其前方(fang)有(you)薄硬鋁(lv)合(he)金振(zhen)(zhen)動(dong)(dong)板。振(zhen)(zhen)動(dong)(dong)板根據(ju)語音(yin)振(zhen)(zhen)動(dong)(dong),振(zhen)(zhen)動(dong)(dong)碳素顆粒(li)(li),碳素顆粒(li)(li)傳(chuan)(chuan)導電(dian)(dian)(dian)流,隨著顆粒(li)(li)的(de)(de)(de)(de)(de)接觸程度(du),電(dian)(dian)(dian)阻(zu)發生(sheng)變(bian)化(hua),生(sheng)成語音(yin)電(dian)(dian)(dian)流。受話(hua)機(ji)接受對(dui)方(fang)的(de)(de)(de)(de)(de)語音(yin)電(dian)(dian)(dian)流后,在線(xian)圈上(shang)生(sheng)成語音(yin)電(dian)(dian)(dian)流引起(qi)的(de)(de)(de)(de)(de)磁力,振(zhen)(zhen)動(dong)(dong)鐵振(zhen)(zhen)動(dong)(dong)板,發出聲(sheng)音(yin)。
無(wu)線(xian)環路-無(wu)繩電話
電話子母機
數字無繩電話
模擬無繩電話
移動電話手機
小靈通(無線電話)
隨著IT技(ji)術的(de)(de)不斷的(de)(de)飛速(su)發展(zhan),嵌入(ru)式(shi)終端設備的(de)(de)處理能力越來越強,21世紀初出現了(le)一(yi)種帶個人(ren)數據助(zhu)理(PDA)的(de)(de)電話機(ji)“智能電話”。
智(zhi)能(neng)(neng)(neng)電(dian)(dian)話除了有完(wan)整(zheng)的(de)固定(ding)電(dian)(dian)話功能(neng)(neng)(neng)外,通常(chang)還(huan)具(ju)有大(da)容量的(de)名片管理(li)功能(neng)(neng)(neng)、來去電(dian)(dian)管理(li)功能(neng)(neng)(neng)、防止(zhi)電(dian)(dian)話騷擾(電(dian)(dian)話防火墻)功能(neng)(neng)(neng)、企業集團電(dian)(dian)話名片(內部名片)管理(li)功能(neng)(neng)(neng),以(yi)及輔助辦(ban)公的(de)許多功能(neng)(neng)(neng),比如:日(ri)程安(an)排、便箋、日(ri)歷(li)、計算器等功能(neng)(neng)(neng)。早期的(de)智(zhi)能(neng)(neng)(neng)電(dian)(dian)話通過撥號上網,具(ju)有一定(ding)的(de)信(xin)息交換(huan)能(neng)(neng)(neng)力,實現了發送短信(xin)、接收文字信(xin)息的(de)功能(neng)(neng)(neng)。隨著固網智(zhi)能(neng)(neng)(neng)電(dian)(dian)話在中(zhong)國近十年的(de)發展,其處(chu)理(li)能(neng)(neng)(neng)力加強,逐漸地增加了智(zhi)能(neng)(neng)(neng)手機(Smartphone)具(ju)有的(de)功能(neng)(neng)(neng)。
智(zhi)能(neng)(neng)電(dian)話(hua)(hua)已有通過(guo)因特網(wang)上(shang)網(wang)的(de)(de)能(neng)(neng)力及較強的(de)(de)多(duo)媒的(de)(de)體功能(neng)(neng)。可(ke)以進行(xing)網(wang)絡(luo)瀏覽、音視頻(pin)的(de)(de)播放、具有電(dian)子(zi)書、電(dian)子(zi)相框等功能(neng)(neng)。同時智(zhi)能(neng)(neng)電(dian)話(hua)(hua)在輔(fu)助辦公、輔(fu)助營銷、娛樂等方面的(de)(de)功能(neng)(neng)也有了大(da)大(da)的(de)(de)加強。在對(dui)傳統(tong)固定(ding)電(dian)話(hua)(hua)顛覆的(de)(de)基礎上(shang),實現了更多(duo)的(de)(de)商務功能(neng)(neng)和PDA功能(neng)(neng)。
環境溫度(du):-10℃~40℃
相對濕度(du):45%~95%
大氣(qi)壓力:860~1060mbar
環境(jing)噪(zao)聲:≤60dB(A)
1、工作頻率:300~3400HZ
2、脈(mo)沖通斷(duan)比:1.6±0.2∶1
3、雙(shuang)音頻(pin)撥號頻(pin)偏:≤±1.5%
4、雙音頻信號電平:①低(di)頻群:-9±3dB;②高頻群:-7±3dB;③頻率組合(he)中高頻分量(liang)比低(di)頻分量(liang)高2±1dB
5、振鈴聲級:≥70dB(A)
6、電聲性能:
①在(zai)0公(gong)(gong)里(li)時(shi),客(ke)觀發(fa)送(song)參考(kao)當量≥+3;在(zai)3公(gong)(gong)里(li)時(shi),客(ke)觀發(fa)送(song)參考(kao)當量≤+15;在(zai)5公(gong)(gong)里(li)時(shi),客(ke)觀發(fa)送(song)參考(kao)當量≤+15。
②在(zai)0公(gong)(gong)里(li)時(shi),客觀接(jie)收參考(kao)當(dang)量(liang)≥-5;在(zai)3公(gong)(gong)里(li)時(shi),客觀接(jie)收參考(kao)當(dang)量(liang)≤+2;在(zai)5公(gong)(gong)里(li)時(shi),客觀接(jie)收摻考(kao)當(dang)量(liang)≤+2。
③在0公(gong)里時(shi)(shi),客觀(guan)側(ce)音參(can)考(kao)當(dang)(dang)量(liang)(liang)≥+3;在3公(gong)里時(shi)(shi),客觀(guan)側(ce)音參(can)考(kao)當(dang)(dang)量(liang)(liang)≥+10;在5公(gong)里時(shi)(shi),客觀(guan)側(ce)音參(can)考(kao)當(dang)(dang)量(liang)(liang)≥+10。
高(gao)科(ke)技電(dian)(dian)(dian)(dian)話(hua)(hua)機的(de)(de)(de)(de)(de)發展(zhan)都是隨(sui)著(zhu)無線通信的(de)(de)(de)(de)(de)發達而形成的(de)(de)(de)(de)(de)。電(dian)(dian)(dian)(dian)話(hua)(hua)機的(de)(de)(de)(de)(de)發展(zhan)趨勢經(jing)過Digital電(dian)(dian)(dian)(dian)話(hua)(hua)機和(he)(he)PCS后發展(zhan)到(dao)可(ke)以用衛星(xing)通信的(de)(de)(de)(de)(de)IMT-200服(fu)務(wu)。IMT-200支(zhi)持信息的(de)(de)(de)(de)(de)高(gao)速傳送(song),Packet,畫像(xiang)等多媒體的(de)(de)(de)(de)(de)服(fu)務(wu),將(jiang)來世界各個地方都可(ke)以使用所(suo)有聲(sheng)音電(dian)(dian)(dian)(dian)話(hua)(hua),電(dian)(dian)(dian)(dian)報用戶直(zhi)通電(dian)(dian)(dian)(dian)路,傳呼和(he)(he)電(dian)(dian)(dian)(dian)子(zi)郵件;隨(sui)著(zhu)電(dian)(dian)(dian)(dian)子(zi)郵件的(de)(de)(de)(de)(de)普及(ji),網絡(luo)也日益(yi)化,網絡(luo)電(dian)(dian)(dian)(dian)話(hua)(hua)已是不可(ke)阻擋的(de)(de)(de)(de)(de)發展(zhan)趨勢。現有的(de)(de)(de)(de)(de)固定(ding)電(dian)(dian)(dian)(dian)話(hua)(hua),已經(jing)不能提供人(ren)們的(de)(de)(de)(de)(de)需(xu)要了。未(wei)來的(de)(de)(de)(de)(de)固定(ding)電(dian)(dian)(dian)(dian)話(hua)(hua)講裝(zhuang)備(bei)攝像(xiang)頭(tou),帶有色彩的(de)(de)(de)(de)(de)液晶顯(xian)示(shi)器,我們在接固定(ding)電(dian)(dian)(dian)(dian)話(hua)(hua)的(de)(de)(de)(de)(de)時候,都能夠看到(dao)雙方。