无码高清视频|成人自拍视频|欧美成人午夜无码A片秀色直播|草美女视频网站|美女被操网站在线观看

單項(xiàng)選擇題

Which ISDN device converts the four-wire BRI signals from an S/T interface into two-wire signals of a U interface?()

A.TE1
B.NT-2
C.TA
D.TE2
E.NT-1

微信掃碼免費(fèi)搜題