Standards, tested in public

Buying a mission-critical system means buying into a standard.
Everything a supplier claims about 3GPP compliance is easy to write in a brochure and hard to prove, and the proof matters on the one day your system has to work with somebody else’s.

There is a place where that gets tested. ETSI runs interoperability test events, called Plugtests, where vendors bring their implementations into the same room and run a published catalogue of test cases against each other. Not a demonstration, not a presentation. Equipment against equipment, for a week.

TASSTA has taken part in the ETSI MCX Plugtests since 2017, and in the ETSI FRMCS Plugtests for rail. This page is what we test there, what the results mean, and what they do not mean.

What a plugtest is, and what it is not

ETSI publishes the test specifications in advance, so every participant runs the same cases. Each pairing of vendors works through them session by session, and ETSI publishes an aggregate result for the event.

Three things are worth knowing before anyone quotes a plugtest at you, including us:

Detailed results are confidential. Participants sign up to rules of engagement and an NDA. Who tested against whom, and how each pairing went, goes to the vendors involved and nowhere else;
No product is certified at a plugtest. It is an interoperability test event, not a certification scheme. Any supplier who tells you their product is plugtest certified is telling you something that does not exist;
The published percentage belongs to the event, not to a vendor. It is the share of all test cases run by all participants that succeeded. It says the ecosystem works. It is not a score for any one company, ours included.

What taking part does tell you is narrower and more useful: the supplier turns up, runs the published cases against other people’s implementations, and fixes what fails.

ETSI MCX Plugtests

Mission-critical push-to-talk, video and data to 3GPP, tested across vendors.

We have taken part since 2017. At the 10th event, 18 to 22 May 2026, participants ran 356 test cases and ETSI reported 92 percent interoperability across the event, with more than 240 people taking part.

What we take into those events: registration and authorization, affiliation, location, OAM, security, functional alias, interworking, MCData, floor control including priorities, queueing and multiple simultaneous talkers, and emergency alert handling.

What we test at the MCX Plugtests

Interworking with the radios you already have

Almost nobody replaces a working radio network in one step. The years in between, when part of an organisation is on TETRA, DMR or analogue radio and part is on broadband, are the years a migration is won or lost.

TASSTA implements Interworking Function connectivity in the MCX environment per 3GPP TS 23.283, for IWF-1 (MCPTT) and IWF-2 (MCData and SDS). In the TASSTA MCX environment it runs through T.Gravity, the gateway from T.XON to TETRA, DMR, analogue radio and SIP telephony.

ETSI FRMCS Plugtests

The Future Railway Mobile Communication System is the successor to GSM-R, and the railways replacing GSM-R this decade are deciding now who they can rely on.

At the 5th FRMCS Plugtests, 27 to 31 October 2025 in Paris, hosted by UIC and organised with ETSI, 96 testing sessions ran more than 300 tests against 3GPP Release 18, and ETSI reported 95.5 percent interoperability. More than 180 delegates took part, over 100 of them on site from 20 countries.

Railway operators and national authorities attend as observers, among them BDBOS, SNCF Voyageurs, SBB, Bane NOR, Trafikverket, Erillisverkot and the French Ministry of the Interior.

TASSTA at the FRMCS Plugtests

Document

Our plugtest documentation lists every area we have taken into the MCX test events, case by case. It is written for the engineer who has to evaluate us. Tell us who you are and what you are evaluating, and we send it.

If you are writing a tender and need to know exactly what we have tested and what we have not, ask. We would rather answer that question before you write the document than after.

Educational resources

Stay ahead with insightful resources.
Explore our latest blogs, case studies, and whitepapers that delve into the intricacies of mission-critical communication, technological advancements, and industry trends.