Abstract: A method manages collisions in a system for interchanging data between portable objects and at least one terminal suitable for co-operating with a plurality of the portable objects simultaneously. The terminal sends out call messages to the portable objects. A portable object conditionally sends a message to the terminal in response to the call with a probability that may be less than 100%, the response containing an identifier specific to the portable object. The receiver receives a response from an identified portable object and in absence of the response colliding with a response sent out by another portable object, a specific data communication link is established between the terminal and the identified portable object. The portable object modulates the probability of response over time depending on whether or not it has itself already responded previously to a call message sent out by the terminal.