New IP-based capability accelerates TETRA networks’ interconnection

Revised ETSI standard allows Inter-System Interface (ISI) connections over IP links

The process of interconnecting two separate TETRA networks will become faster, easier, and more cost-effective with the revised ETSI standard for the TETRA Inter-System Interface (ISI) that now includes IP connectivity. To date, interconnection of individual TETRA networks via the ISI required a dedicated E1 link. This can be expensive and sometimes impossible to lease because providers no longer support circuit switched connections.

The 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 robust and unique 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 in order 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.


About TCCA

TCCA represents all standard mobile critical communications technologies and complementary applications. Our Members are drawn from end users, operators and industry across the globe. We believe in and promote the principle of open and competitive markets worldwide through the use of open standards and harmonised spectrum. We maintain and enhance the TETRA Professional Mobile Radio (PMR) standard, and drive the development of common global mobile standards for critical broadband. TCCA is a 3GPP Market Representation Partner and a member of the Mission Critical Open Platform (MCOP) project. Our Members actively contribute in 3GPP working groups.  To find out more, please visit

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