A、環(huán)形 B、線形 C、星形 D、樹(shù)形
A、G.652D B、G.657B C、G.652B D、G.657A
A、話音業(yè)務(wù)Voice service B、數(shù)據(jù)業(yè)務(wù)Data service C、視頻業(yè)務(wù)Video frequency service D、CATV業(yè)務(wù)CATV service