Since the first networks were implemented more than 20 years ago, TETRA has become the critical communications technology of choice around the world. While critical broadband systems are emerging, they will only provide a partial solution for many years to come, and TETRA will still be required to provide very high resilience secure voice and short data functionality. ETSI’s Technical Committee TETRA and Critical Communications Evolution (TC-TCCE) is responsible for the TETRA standard and is developing key interworking standards to allow critical broadband and TETRA terminals to be used across both types of network. The TETRA standard itself continues to be improved and maintained, including the specification of new encryption algorithms to ensure TETRA is secure for the next 15-20 years in the face of increasing cyber crime.