The WDM modules are passive optical devices. They multiplex and de-multiplex the optical signals (wavelengths acc. to ITU-T G.694) of the line interfaces in full duplex. The multiplexing component of these modules merges the channels onto a single fiber. The de-multiplexing component receives this signal on the other end of the line and separates the signals back into single ITU-T channels. Different types of filter modules are available. Additional optical supervisory channel.

CWDM:

• Granularity down to 4 channels
• Up to 16 channels
• In-service upgrade from 8 to channels

DWDM:

• Granularity down to 8 channels
• Up to 64 channels, < 2.7 Gbps
• Up to 32 channels, @ 10 Gbps