Due to the incompatibilities that exist in current 800 MHz trunked radio systems supplied by the various manufacturers, the FCC allocated five conventional radio channels for the purpose of mutual aid. These channels were part of the 821/866 MHz spectrum allocation released in the late 1980's and are commonly called the NPSPAC (National Public Safety Planning Advisory Committee) mutual aid channels. These five common channels are allocated nationwide and are licensed by a number of entities in the COG under the auspices Region 40. The Region 40 Regional Review Committee is the group that oversees the tasks as directed by the FCC and is responsible not only for NCTCOG, but also the Texoma COG, Ark-Tex COG, and East Texas COG.
NPSPAC Plan [PDF]