Devices enabling radiotelephones to manage filtering and interference

Claim 1

In combination with a radiotelephone, a device comprising: detection means for detecting that the radiotelephone is present in an area of jamming or of filtering; switchover means for changing over between a normal operating mode of the radiotelephone and a filtered mode, in response to a signal received from said detection means, the switchover means comprising; means for displaying on the screen, when the radiotelephone is operating in filtered mode, a message indicating that the radiotelephone is in an area of jamming, and for displaying on the screen a message and/or for emitting a flashing signal indicating that a call is occurring in the jamming area; and means for emitting a sound signal, when the radiotelephone is operating in normal mode, upon exit from the jamming area if a message or a call occurred in the jamming area; and a link formed by an electrical cable between an antenna outside the filtered or jammed area and a connecting socket of the radiotelephone, with the radio reception of the antenna of the radiotelephone being cut off while said radiotelephone is in said jammed area.