1) TETRA data applications are evolving to meet user needs such as field control, surveillance, and information sharing. Examples include process control using telemetry, fleet and task management using positioning data, and field documentation and reporting using prepared templates. 2) Commercial networks are not always reliable enough for critical communications during emergencies. TETRA provides mission critical voice and data services through a wide area network with guaranteed delivery. 3) Key TETRA data services include status messages, short data service, and IP packet data, enabling applications like remote sensor monitoring, visual command centers, and mobile access to databases.