Checking the Personal Identification Number of a mobile subscriber

The invention relates to method for checking a personal identification number (PIN) of a subscriber in a mobile equipment (500) employed in a mobile communications system (600), the mobile equipment containing a protected subscriber identity (IMSI, ITSI). The method comprises the steps of requesting (203) the user of the mobile equipment the personal identification number (PIN) of the subscriber, checking (103) the validity of the personal identification number entered by the user, repeating (109) these steps provided that the user does not enter the valid personal identification number, and, when the number of requests (203) and checks (103) of the identification number exceeds a predetermined threshold value, blocking (111) the mobile equipment. According to the invention, protection of a protected subscriber identity is released (112), thus finding out the identity of the subscriber; the subscriber identity as well as and an indication that the mobile equipment has been blocked are transmitted the mobile communications system.