Patent ID: 8446249
Filing Date: 2013-05-21
Classification: G07C,G08C

Abstract:
1. A method of controlling access to an area, the method comprising: receiving an identification code identifying a user, the identification code having been transmitted by a first communications unit at a first transmission power, the receiving being performed using a second communications unit and a third communications unit; transmitting an acknowledgement code at a second transmission power from the second communications unit, the acknowledgement code signifying that the identification code has been successfully checked against an authorized identification code; transmitting the acknowledgement code at the second transmission power from the third communications unit, the second transmission power being lower than the first transmission power, the transmitted acknowledgement code from the second communications unit being receivable by the first communications unit and the transmitted acknowledgement code from the third communications unit being unreceivable by the first communications unit; receiving an access code from the first communications unit using the second communications unit; determining the user's location relative to the second communications unit based on the receipt of the access code by the second communications unit; granting access to the area if the access code agrees with an original access code; and providing guidance information to the user based on the user's determined location.