A.同步通信 B.單工通信 C.異步通信 D.雙工通信
A.把模擬信號(hào)轉(zhuǎn)換為數(shù)字信號(hào) B.數(shù)字信號(hào)轉(zhuǎn)換為模擬信號(hào) C.模擬數(shù)字間相互轉(zhuǎn)換 D.全不正確
A.綜合業(yè)務(wù)數(shù)字網(wǎng) B.非對(duì)稱數(shù)字用戶環(huán)路 C.數(shù)字?jǐn)?shù)據(jù)網(wǎng) D.電話網(wǎng)寬帶