Recommendation ITU-T G.695 provides optical parameter values for physical layer interfaces of coarse wavelength division multiplexing (CWDM) applications with up to 16 channels and up to 100 Gbit/s. Applications are defined using two different methods, one using multichannel interface parameters and the other using single-channel interface parameters. Both unidirectional and bidirectional applications are specified. In this version of this Recommendation, an application code for 4-channel PAM4 100G black box applications has been added, which is suitable for carrying 4×FOIC1.1-RS and FOIC4.4-RS (400G striped across four physical lanes).