TETRA, or Terrestrial Trunked Radio is a professional mobile communication system based on time-division multiple access (TDMA) technology. It is designed and developed by ETSI (European Telecommunications Standards Institute), to meet the requirements of professional departments in Europe for mobile communication, and it is a global standard for digital trunking radio. The TETRA standard was initially used in Europe but is now rapidly implemented in other parts of the world. The complete TETRA system serves mission-critical organizations and their users, can provide real-time and reliable communication, and is used in different industries such as public safety, transportation, utilities, oil & gas, and more.