A.免提 B.脈沖,雙音頻發(fā)號(hào) C.號(hào)碼存儲(chǔ) D.免提/揚(yáng)聲功能
A.1.5m B.1.2m C.1m D.0.8m
A.691 B.630 C.678 D.769