This Recommendation describes the Transmission Convergence Layer for Gigabit-capable Passive Optical Networks a family of flexible access networks capable of providing a range of broadband and narrow-band services. Systems operating at rates of 1.24416 and 2.48832 Gbit/s downstream, and 0.15552, 0.62208, 1.24416, and 2.48832 Gbit/s upstream are described. It deals with specifications for Gigabit PON Transmission Convergence (GTC) frame, message, ranging method, OAM functionality and security.

This Recommendation forms an integral part of the G.984 series of ITU-T Recommendations that, together, specify a single coherent set of access transmission systems.

The G.984 series differs from the previous G.983 series primarily in that higher line bit rates are described. As a consequence of this difference, the G.984 series deals with many technical issues and features in a manner different from the G.983 series. The two systems are not interoperable.