A.常規(guī)模擬電話撥號(hào) B.數(shù)字電話撥號(hào) C.無(wú)繩電話撥號(hào) D.手機(jī)撥號(hào)
A.active-standby B.active-active C.standby-standy D.以上選項(xiàng)都不對(duì)