D1-D12 are digital communication path bytes, of which D1-D6 are used for the regeneration section and D7-D12 are used for the multiplexing section.

Single-fiber bidirectional WDM systems use only one optical fiber to transmit optical signals in both directions at the same time. Light signals in both directions should be arranged at different wavelengths.

EPL services use ports and bandwidth exclusively, and different users may need to share resources. Which of the following methods can be used to isolate user data?

When you configure services on a per-NE basis, which of the following protection scenarios does not require subnet configuration before subsequent protection operations?

Which of the following alarm/event dump modes does U2000 support? (Multiple choice)