One interface for an entire military fleet

A modern armed force runs dozens of vehicle types from many manufacturers, each historically arriving with its own diagnostic tool, connector and protocol. That fragmentation is slow and expensive in the field. The civilian vehicle world tackled a version of this with standard diagnostic protocols and APIs; defence is now doing the same — and adding a sovereignty requirement, because the tooling and the data touch national security. Memory-safe languages such as Rust are part of the same shift: in mission-critical embedded software, security has to be designed in, not bolted on.

FMV, the Swedish Defence Materiel Administration, procures and sustains the equipment of the Swedish Armed Forces — including a large, mixed fleet of military vehicles. Keeping that fleet diagnosable and maintainable, across many manufacturers and decades of service, is a national-scale logistics problem.

Almost every vehicle type brought its own diagnostic tool, connector and protocol. Technicians in the field needed one thing that could talk to all of them — read faults, run the manufacturers' own diagnostics, and log how vehicles are actually used — on hardware rugged enough for military service and trusted enough for a sovereign defence customer. And it had to last: with a platform life measured in decades, the software itself had to stay maintainable for the long haul.

For well over a decade, unbroken, Diadrom has worked alongside FMV as an embedded-development partner — requirements engineering, software development in C++ and, increasingly, memory-safe Rust, and test and validation — drawing on diagnostics knowledge across a wide variety of military vehicles, both on- and off-board.

The centrepiece is the Vehicle Communication Box (VCB): a rugged, EMC-hardened Linux device that interfaces to many vehicles in a fleet and runs diagnostic applications on- and off-board, with a wide selection of interfaces for different physical communication layers. Instead of a drawer full of manufacturer-specific tools, a technician connects one box.

The VCB collapses a fragmented toolchain into a single, trusted device. Where each manufacturer and each protocol once meant another tool to buy, learn and carry, FMV's technicians get one rugged box that connects to the fleet, runs the OEMs' own diagnostics, and logs how vehicles are used. Built on a sovereign Swedish supply relationship and modern, memory-safe software, it is designed to stay maintainable across the platform's full multi-decade life — and an unbroken delivery record now well into its second decade is itself the proof that the model works.

As fleets become more software-defined and more connected, the case for a single, secure, sovereign diagnostic interface only grows — and security-by-design, including languages like Rust, moves from nice-to-have to baseline. FMV's lesson for peers: treat fleet diagnostics as long-lived national infrastructure, standardise the interface, and invest in a partner who will still be there in a decade.