Dispersion compensation is not required for 40Gbit/s and 100 Gbit/s coherent systems because the dispersion tolerance of coherent boards is large. NG WDM products do not support hybrid transmission of non-coherent and coherent networks.

A. True

B. False

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 100G coherent system is ePDM-QPSK.

B. The modulation technology used in a 40G coherent system is ePDM-BPSK.

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.

Which of the following OTN trails does not need to be manually configured on an ROADM site, and can search out directly?

A. OSC

B. OCh

C. OMS

D. OTS

Before querying bit errors and optical power on the U2000, you need to perform the () operation. Otherwise, the corresponding data cannot be queried.

A. Enabling the NE Performance Monitoring Time

B. Creating the logical fiber

C. Synchronizing NE data

D. Configuring data

Loopback is a common operation for routine maintenance and troubleshooting. Which of the following statements about loopback operations are incorrect?

A. The hardware loopback is performed by using the fiber jumper or self-loop cable to perform the loopback on the optical port or electrical port.

B. When performing a hardware loopback on an optical port, you need to add an optical attenuator.

C. After the outloop is performed, the signals are transmitted to the internal.

D. After the inloop is performed, the signals are transmitted to the external.

In the scenario where the non-convergence OTU processes OTN standard signals, both A and B are WDM sites. The OTU at station A accesses four channels of R_LOS signals on the client side. After being processed in the middle part and on the WDM side of the OTU at station A, the alarm signals are then sent to station B. The ODUk_PM_AIS alarm of the corresponding channel is generated in the middle part of station B. The ODUk_PM_AIS alarm is detected in the client device.

A. True

B. False

The overhead ratio is a factor that affects the error correction capability of the FEC technology. Generally, when the same FEC encoding/decoding is used, the higher the overhead ratio is, the larger the net coding gain is.

A. True

B. False

Which of the following signals can be used as input or output signals of an external clock interface?

A. 2.048 MHz

B. 2.048 Mbit/s

C. 155 Mbit/s

D. 34 Mbit/s

Which of the following is not a precaution after board replacement?

A. Record the settings of jumpers and DIP switches on the board.

B. For functional units that have backups, check whether the switchover is normal.

C. Check the indicator blinking status of the board and ensure that the board works properly.

D. Ensure that no abnormal alarm.

The causes of discrete services are as follows:

A. The cross-connection configuration on the NE is incorrect.

B. The logical fiber connection of the NE is inconsistent with the physical fiber connection.

C. The configuration data on the NE side is not uploaded to the U2000.

D. A subnet service whose source or sink port is not in the management scope of the U2000 is available.