Terrestrial Trunked Radio is known as TETRA. It was developed by the European Telecommunications Standardization Institute. By using TETRA we are benefited in many ways over in other technologies. The much lower frequency used gives longer range, which in turn allows very high levels of geographic coverage with a smaller number of transmitters, therefore cutting infrastructure costs. TETRA has a High ghostly effectiveness. The one too many group call is normally set-up within 0.5 seconds, so that TETRA have a very fast call set-up.
It also works at very high speeds and it also supports a variety of emergency calling method. The communication will ensure the success even during the overload condition because the systems have several instruments, which is intended into the protocols and radio limitations. In the absence of a network mobiles can use ‘direct mode’ whereby they can share the channels directly. TETRA offers a point-to-point function that established analogue emergency services were the radio systems did not provide this facility.
