TEM28 is the Ethernet convergence tributary board. Which of the following descriptions about the TEM28 board are correct? (Multiple Choice)

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

Which of the following subracks does not support the configuration of packet board?

Customer Example 1+1 protect when using different routes, the same wavelength cannot be used for the working wavelength and the guard wavelength.

WDM multiplexes optical signals at multiple rates (wavelengths) through a single fiber for transmission. The digital signals carried by these optical signals must have the same rate and data format.