A.64kb/s B.2Mb/s C.8Mb/s D.34Mb/s
A.編譯碼 B.模數(shù)轉(zhuǎn)換 C.2/4轉(zhuǎn)換
A.模擬用戶 B.數(shù)字用戶 C.模擬中繼 D.數(shù)字中繼