Professional mobile system - TETRA over IP and IP over TETRA

Terrestrial Trunk Radio is a system used for professional mobile radio or public access mobile radio. TETRA is designed for different institutions: Dars, Telekom, airports, security organisations, etc. The system is applied for wireless technologies like IP over Tetra, Tetra over IP, and WAP. We describe this kind of system (IP/TETRA, TETRA/IP, WAP). The most important point of the system is encryption data for different kind of users. We describe a system which already exists in Slovenia.