Abstract: In a GSM type system, home location register resets after some incidents are programmed from a back-up register. The invention proposes that mobile service switching centers create a difference between two classes of update requests which they send to the home location register in two different situations. In the first class a message following a change of area by a mobile station takes priority. In the second class a message follows a home location register reset and tends to (frequently unnecessarily) re-establish the conformity of the data in the home location register and in the visitor location registers of the centers. The second class is assigned a low priority level which prevents problems with the availability of the home location register. Application to telephony.