This European Telecommunication Standard (ETS) contains the full specification of the speech codec for use in the Trans-European Trunked Radio (TETRA) system.
DS/ETS 300395-2:1998 history
1998DS/ETS 300395-2:1998 Terrestrial Trunked Radio (TETRA) - Speech codec for full-rate traffic channel - Part 2: TETRA codec