The following description of 1+1 and 1:1 optical line protection, the fault is (). (Multiple Choice)

• A.1+1 optical line protection and 1:1 optical line protection use the same protection board
• B.According to different placement of OLP boards in the network, 1+1 optical line protection can be divided into 1+1 OMS path protection and 1+1 OTS path protection.
• C.The main difference between 1:1 optical line protection and 1+1 optical line protection is whether the APS protocol is required.
• D.1:1 optical line protection switching mode can only be double-ended switching

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Which of the following statements about the modulation technologies of the 40Gbit/s and 100Gbit/s coherent systems are correct?

• A.The modulation technology used in a 40G coherent system is ePDM-BPSK.
• B.The modulation technology used in a 100G coherent system is ePDM-QPSK.
• C.The modulation technology used in a 40G coherent system is ePDM-QPSK.
• D.The modulation technology used in a 100G coherent system is ePDM-BPSK.

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When the working channel protected by the optical line fails, it cannot be automatically switched to the protection channel. What are the possible reasons? (Multiple Choice)

• A.Artificially issued a lock command
• B.Protection group parameter configuration error
• C.The protection channel is faulty
• D.Waiting for the recovery time to be set too long

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The transmission windows of 1310 nm and 1550 nm are low loss windows. In DWDM systems, only the 1550nm transmission window is used. Which of the following is the main reason?

• A.The nonlinear effect in the 1550nm wavelength region is very small.
• B.The operating wavelength flatness area of EDFA is contained in this window.
• C.None of the above
• D.The 1550 nm wavelength region is suitable for long-distance transmission.

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Which of the following description of the single station commissioning is wrong?

• A.If the input voltage of the equipment is not within the required range, suggestions for rectification should be proposed.
• B.Single station hardware check is complete, make sure all power switches are in the off position
• C.In case of power failure, the contact board can be used without anti-static wrist or anti-static gloves.
• D.It is strictly forbidden to plug and unplug the power plug and PIU board.

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