() means that each up-wave or down-wave port can only go up and down with a fixed wavelength.

OTUk_ENC indicates that the OTUk bit error exceeds the threshold. What are the options for the following description of the bit error detection horizontal mode? (Multiple choice)

Wavelength division multiplexing technology is to multiplex optical signals of different wavelengths into the same optical fiber for transmission.

A VC-4 can transmit () VC-12, that is () 2.048 Mbit/s signals.

In the non-converged OTU processing OTN standard signal scenario, both A and B are WDM sites, and the client side of the OTU at station A receives the RLOS signal; after processing the alarm at the WDM side of the OTU, it is transmitted to station B The OTU WDM at station B will detect the ODUk PM AIS alarm and generate an SF event; trigger channel service switching. The alarm continues to be sent to the downstream client device of station B, and an ODUK_PM_AIS alarm is reported to the client device.