The OTU2 frame length is approximately four times the OTU1 frame length

• A.FALSE
• B.TRUE

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The following clock networking optimizations are wrong:

• A.Under the standard SSM switching protocol, the clock can be configured as bidirectional, but it must not be configured as a ring. Enable the extended SSM protocol to solve the clock loop problem by assigning a clock ID to the clock source.
• B.For PDH, ITU-T stipulates that 4 consecutive odd frames sa4~sa8 in 2M bit signal TS0 are used to transmit quality information, and SDH uses S1 byte b5-b8 to transmit the same quality information. SDH equipment can automatically extract SSM information from the 2Mhz external clock signal provided by the BITS equipment, so as to know the quality level of the timing signal.
• C.Timing reference clock transmission link, requires that at most N=20 network elements, the transit office clock must be introduced for clock reshaping and regeneration (high-quality clocks are serialized), up to K=10 transit office clocks, clocks The maximum number of G.813 clocks on the link does not exceed 60.
• D.Under the non-SSM switching protocol, the clock network can only be configured as one-way and cannot form a loop.

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In a certain wavelength division system project, the 1st-20th wave LSX is configured, and the M40 output port is tested with a spectrum analyzer during commissioning. It is found that the optical power of the 20th wave is significantly lower than that of the other 19 waves. The possible reason is (multiple choice)

• A.The RX port of the 20th wave LSX has an additional 5dB fixed light attenuation
• B.The 20th wave LSX WDM side light emission is too small
• C.Wave 20 LSX wavelength shift
• D.The insertion loss of the 20th channel corresponding to M40 is too large

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What should I pay attention to when swapping antennas? (multiple choices)

• A.During the commissioning period, the weather conditions are good, and there is no rain/snow/fog impact between the two sites
• B.If the microwave link adopts a 1+1 protection configuration and uses one antenna, turn off the power of the backup ODU before switching the antenna
• C.Turn on AM function
• D.ATPC function is off

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There is a lower limit for the length of the Ethernet frame. What is the main reason for this?

• A.Carrier monitor
• B.Improve network bandwidth utilization
• C.Multi-point access
• D.Conflict detection

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