Mobile communication terminal device and method of preventing incorrect information rewriting

摘要

In a mobile communication terminal device, a serial number for use in charging control of a subscriber and so on is prevented from being incorrectly rewritten and hence the subscriber is prevented from being incorrectly charged. An electrically writable/ersable memory 10 in the mobile communication terminal device includes a first storage region RG1 for storing information as an encoded serial number and a storage region RG2 for storing said serial number before encoding, and further a CPU 2 includes means for decoding said encoded information and comparing it with said unencoded serial number, and disabling the mobile communication terminal upon incoincidence of the decoded information and the unencoded information.