Patent ID: 7418594

Claim:
A mobile unit authenticating method which authenticates a first mobile unit of a user when service is offered through communications of digital content between an installed terminal and the first mobile unit, comprising the steps of: connecting the first mobile unit of the user to the installed terminal; connecting the first mobile unit to a second mobile unit of the user which has been authenticated by another system; transmitting identification information about the second mobile unit to the installed terminal through the first mobile unit; transmitting the identification information about the second mobile unit from the installed terminal or an installed terminal center which integrally manages a plurality of installed terminals including the installed terminal to a management center which manages the identification information about the second mobile unit when the installed terminal receives the identification information about the second mobile unit; determining whether or not the second mobile unit is valid based on the received identification information about the second mobile unit when the management center receives the identification information about the second mobile unit; transmitting a determination result to the installed terminal or the installed terminal center; setting service between the installed terminal and the first mobile unit as allowed in the installed terminal if it is determined that the second mobile unit is valid; and if service is set as allowed, processing, in the installed terminal, digital content provided by the first mobile unit in accordance with a requested service.