In fibre-channel technology, a transmission word that uses 8B/10B mapping and begins with the K28.5 character. Ordered sets occur outside of frames, and include: frame delimiters, which mark frame boundaries and describe frame contents; primitive signals, which indicate events; and primitive sequences, which indicate or initiate port states. Ordered sets are used to differentiate fibre-channel control information from data frames and to manage the transport of frames. See also data word.