PON（Passive Optical Network：无源光纤网络)技术是一种点到多点的光纤接入技术，它由局端侧的OLT、用户侧的（）以及ODN组成。

A.quadrilateral

B.polygon

C.square

D.optical

A. And its functions include ().

B.Interface rate configuratio

C.Digital diagnosis for the optical interface

D.Auto shutdown function of the optical interface laser

E.Ethernet synchronizatio

A.Optical transmit unit (OTU)

B.Optical add/drop multiplexer (OAD)

C.4-channel 644M sub-rate convergence board(SRM42)

D.2-channel Gigabit Ethernet convergence board(GEM2)

Which of the following should be noted when performing hardware loop on optical interface through fiber？()

A.Never look straight at output optical interface or tail fiber end surface that connects with it.

B. First you must disable laser output to avoid too strong output power burning down tail fiber end face.

C. Use an optical power meter to measure input interface power to avoid receiver burning down due to overload.

D. If there are no attenuators, loosen the receiver and tighten the transmitter to prevent optical input from overloading.

A.光线路局端，光网络终端，光网络单元，光分配网

B.光线路局端，光网络单元，光分配网，光网络终端

C.光线路局端，光网络单元，光网络终端，光分配网

D.光网络单元，光线路终端，光网络终端，光分配网

ld’s longest high-speed optical fiber link connected _____ with London.

A.effective

B.passive

C.relative

D.expressive

A.被动的

B.积极的

C.主动的