A.編譯碼 B.模數(shù)轉(zhuǎn)換 C.2/4線轉(zhuǎn)換
A.模擬用戶B.數(shù)字用戶C.模擬中繼D.數(shù)字中繼
A.模擬信號(hào) B.數(shù)字信號(hào) C.模擬信號(hào)和數(shù)字信號(hào)