Reset the MMSI of a Simrad AI50

Have you acquired a used Simrad AI50 AIS transponder that still broadcasts the previous owner’s MMSI? This is the classic lock on this model: on a Class B AIS, the MMSI locks after the first entry, and Simrad no longer resets the AI50. Skysat resets it for you, on-site in Carnac.

Why the AI50’s MMSI locks

On a Class B AIS like the AI50, the MMSI (the 9-digit identity number of the station) can only be programmed once. Once entered and confirmed, the field locks: this is a regulatory safety feature to prevent changing the transmitted identity on the fly. The Navico configuration software, proAIS2, then displays the MMSI field in grey: it cannot be modified via normal means.

Why Simrad no longer resets the AI50

The official solution — having the MMSI reset by the manufacturer or an authorized dealer — no longer exists for this model: the AI50 is end-of-life and Simrad/Navico no longer supports it. Owners of a used AI50 are left without an official recourse. This is precisely the service we provide.

Why this requires a workshop procedure

Resetting the MMSI of an AI50 requires opening the unit, intervening on its configuration, then correctly reprogramming the station’s identity. A sloppy manipulation can leave the transponder in an inconsistent state — and AIS is a safety-critical equipment. Our technicians perform the operation properly, test the unit, and return it ready to receive your own MMSI.

After the reset: your MMSI and the ANFR

Resetting returns control of the unit to you; responsibility for the transmitted identity comes with it. You must then program your own MMSI, declared for your boat with the ANFR (maritime.anfr.fr) under your ship station license. Never program another vessel’s MMSI: an AIS transmits continuously, and an incorrect MMSI broadcasts a false identity — dangerous in search-and-rescue situations. We can guide you through this step.

Reset or replace the AI50?

If the AI50 is working well and the only issue is the locked MMSI, resetting is the right solution — no need to buy new hardware. However, if you are upgrading your electronics, switching to NMEA 2000, or want better visibility in dense traffic, a recent Class B+ AIS (SOTDMA, 5 W) may be justified. Tell us what you have on board: we’ll give you an honest recommendation.