What is TETRA?

Terrestrial Trunked Radio (TETRA) is a digital radio standard in trunking developed by the European Telecommunications Standards Institute (ETSI). The standard is sufficiently detailed and open that there are currently different terminal manufacturers on the market whose equipment can interoperate in networks of different infrastructures.

The possibility of complete interoperability between products from different manufacturers is a differential advantage of the open standards developed by ETSI. The TETRA standard is supported by various independent manufacturers, which encourages competitiveness by providing the user with a second source for product selection.

TETRA is currently used worldwide, providing security, reliability, and robustness in critical communications.

The TETRA Association was created in December 1994 as an independent association, and today it includes more than 150 organizations worldwide (see www.tetramou.com).

TETRA Systems in Remote Control

TETRA is a narrowband private network whose use in remote control applications is increasingly common as it provides certain advantages such as network reliability and availability, and the possibility of using existing infrastructures at a low cost, even with coverage in areas not normally covered by other public networks. Often, remote facility management systems do not require high speed and bandwidth, but high availability and reliability, and in these areas TETRA guarantees the service (let’s not forget that it is a network originally created for emergency systems, firefighters, police, ambulances, etc.).

The data communication protocols that use the TETRA medium must be prepared for this. The DNP3 telemetry protocol is very suitable for use in TETRA networks (due to the advantages we have seen in the previous chapter). Given the limitations in bandwidth and speed of this network, the implementation of an inadequate communications strategy (use of industrial protocols or those based exclusively on “pull”) can lead to undesirable results in the project.

There are TETRA routers oriented to remote control and M2M communication specifically designed for this purpose on the market. These are data terminals that support the transmission of industrial protocols (DNP3, Modbus, IEC60870, etc…) in a transparent way, without the need to use AT commands from the control station. In addition, they have transmission optimization mechanisms such as the use of compression algorithms to better exploit the limited bandwidth of TETRA networks, as well as routing tables for sending IP packets to different remote equipment.

TETRA SDS Communications

Through the TETRA SDS protocol, it is possible to send serial messages using the control channel. Communications are slower but are not interrupted by voice.

TETRA SDS Network through a switch

TETRA Packet Data Communications

Data transmission in TETRA via Packet Data allows us a fast transfer of IP data. This is a service that depends on the TETRA infrastructure and whose great advantage is that it supports IP protocols (interrupted by voice messages).

TETRA IP Packet Data Network with routing