Patent ID: 7103310

Claim:
A method of restricting the use of a radio terminal able to communicate with a mobile radio network adapted to transmit an acknowledgment signal in response to receiving a network access request from the terminal, the method comprising the following steps: intercepting a network access request sent by the terminal; evaluating a selective restriction criterion on the basis of parameters relating to the intercepted access request; and sending a radio signal to jam the acknowledgment signal if the selective restriction criterion is satisfied, wherein the radio signal for jamming the acknowledgment signal is a radio signal adapted to produce interference with said acknowledgment signal, and wherein a start time for reception of the acknowledgment signal by the terminal and an end time for reception of said acknowledgment signal by the terminal are estimated and the sending of the jamming radio signal starts before the estimated start time for reception of the acknowledgment signal by the terminal and extends beyond the estimated end time for reception of said acknowledgment signal by the terminal.