A revision to the ETSI standard for the TETRA Inter-System Interface (ISI) has added support for IP connectivity

This change will make the process of interconnecting two separate TETRA networks faster, easier, and more cost effective, as prior to this change a dedicated E1 link was required. This can be expensive and sometimes impossible to lease because providers no longer support circuit switched connections.

ISI is the mechanism that enables separate secure TETRA networks to interconnect. For first responders, this is essential for communications continuity if working in regional or national cross-border areas. Other examples could be individual networks used by different organisations needing to interwork in an environment such as an airport, or a municipality where critical user groups, such as public transport and city fire services using their own TETRA networks, need to communicate securely for effective collaboration.

Current TETRA systems are interoperable in terms of hardware and software from different manufacturers, due to the TETRA Interoperability Process (IOP) run by TCCA through its Technical Forum (TF). To ensure the new IP option for ISI is included in the IOP Testing & Certification, the TF’s ISI Working Group has been working in parallel with the ETSI revision process. The Group has written new ISI TETRA Interoperability Profiles (TIPs) which are the basis for the Interoperability Testing. The new TETRA ISI TIPs are now available in the Members’ area of TCCA’s website.

Each TIP is based on ETSI TETRA standards. The TIPs primarily constitute a clarification of the standards and may impose limitations to achieve a range of fully compliant and interoperable TETRA equipment available to the market. TCCA contracts ISCOM (Istituto Superiore delle Comunicazioni e tecnologie dell’Informazione), a laboratory of the Italian Ministry of Communications, as the independent TETRA testing & certification authority responsible for supervising the testing sessions.

Author: Sam Fenwick