A.電路層(CircuitLayer,CL) B.路控制子層(LogicalLink Control,LLC. C.傳輸通道層(Transmission Path layer,TP) D.傳輸介質(zhì)層(Transmission Media layer,TM)
A.0.18dB/km B.1dB/km C.2dB/km D.3dB/km
A.光時(shí)域反射儀 B.光功率計(jì) C.光源 D.以上都不是