ETSI PRETS 300 393-2-1994 Radio Equipment and Systems (RES); Trans-European Trunked Radio (TETRA); Packet Data Optimized (PDO) Part 2: Air Interface (AI)
1999ETSI PRETS 300 393-2-1999 Terrestrial Trunked Radio (TETRA); Packet Data Optimized (PDO); Part 2: Air Interface (AI)
1998ETSI PRETS 300 393-2-1998 Terrestrial Trunked Radio (TETRA); Packet Data Optimized (PDO); Part 2: Air Interface (AI) Second Edition
1995ETSI PRETS 300 393-2-1995 Radio Equipment and Systems (RES); Trans-European Trunked Radio (TETRA); Packet Data Optimized (PDO); Part 2: Air Interface (AI)
1994ETSI PRETS 300 393-2-1994 Radio Equipment and Systems (RES); Trans-European Trunked Radio (TETRA); Packet Data Optimized (PDO) Part 2: Air Interface (AI)