Huawei TN58NS4T61 Board realizes the relay of 1 optical signal, and the wavelengths of both ends of the transceiver are OTU4 optical signals that comply with the DWDM standard wavelength recommended by ITU-T G.694.1. The optical receiving module receives the optical signal to be relayed through the “IN” optical port and completes the O/E conversion. The electrical relay module performs signal decoding, overhead processing, and encoding. In this process, the electrical signal-based shaping, regeneration, and retiming are completed and packaged into the OTN frame signal format. The coded signal is sent to the optical transmitting module, and after E/O conversion, the OTU4 optical signal of the DWDM standard wavelength conforming to the ITU-T G.694.1 recommendation is sent. The converted optical signal is output from the “OUT” optical port. Huawei TN58NS4T61 Board can be created as “57NS4” on the network management system and replace TN57NS4. No software upgrade is required for replacement. TN58NS4 occupies 1 physical slot, TN57NS4 occupies 2 physical slots. When TN58NS4 replaces TN57NS4, it needs to be inserted in the right slot of the original TN57NS4 slot. No more single board can be inserted in the free physical slot. The replaced single board only has the function of TN57NS4. It can be replaced only when both the sending and receiving boards adopt SDFEC2 encoding and the board types are the same
