Recommendation ITU-T G.9902 contains the physical layer (PHY) and the data link layer (DLL) specifications for the ITU-T G.9902 narrowband orthogonal frequency division multiplexing (OFDM) power line communication transceivers, operating over alternating current and direct current electric power lines over frequencies below 500 kHz.

This Recommendation uses material from Recommendations ITU-T G.9955 and ITU-T G.9956; specifically material from the main body and the annexes pertaining to the main body. New technical material has not been introduced in this version.

The control parameters that determine spectral content, power spectral density (PSD) mask requirements and the set of tools to support the reduction of the transmit PSD can be found in Recommendation ITU-T G.9901.