Patent ID: 7778669

Claim:
An electronic device that receives data from an external device over a communication network, comprising: a memory unit which stores said data received from said external device, and stores a data number of said data in association with unique information stored in an external memory medium removable from the electronic device; a read-out unit which reads out said unique information from said removable external memory medium with said external memory medium loaded; a receiving unit which receives an instruction of selecting data to be acquired from said external device; a data presence/absence determination unit which determines whether or not data identical to said data indicated by said selection instruction is already stored in said memory unit; and an operation control unit which performs a control in such a manner as to change an association of said data number of said data and said unique information stored in said memory unit when said data presence/absence determination unit determines that said data identical to said data indicated by said selection instruction is already stored in said memory unit, and requests said external device to send said data indicated by said selection instruction when said data presence/absence determination unit determines that said data identical to said data indicated by said selection instruction is not stored in said memory unit, wherein said unique information comprises at least one of a subscriber number, a telephone number, a user name, an electronic mail address, a network identification number, a media access control (MAC) address and an IP address.