| 摘要 |
PROBLEM TO BE SOLVED: To prevent the abuse such as the illegal copy (clone) of the inherent information of user stored in a nonvolatile memory. SOLUTION: An eigenvalue setting means consists of a variable resistor 125 and an A/D converter 126. The moving element position of the resistor 125 is moved and adjusted at random, and the converter 126 outputs a random eigenvalue VP for every telephone set. A nonvoltile memory 117 stores the inherent information of a user and also the above-mentioned eigenvalue VP as an inherent key, e.g. when produced. For instance, when the power is on, a normal operation continues as a telephone set only when the eigenvalue VP outputted from the converter 126 coincides with the inherent key stored in the memory 117. When the contents of the nonvolatile memory of another telephone set are copied into the memory 117, the normal operation does not continue but the operation is stopped. Thus, the abuse such as the illegal copy of the inherent information of the user is prevented.
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