摘要 |
The invention relates to a warning device for signaling the presence of a radio frequency communication. The system includes an indicator perceptible to a user and an activation circuit to sense or detect energy originating from the communication and to activate the indicator. The device is distinguished in that the indicator is a vibrator. The invention also relates to a radio frequency communication device, such as a chip card, a passport, an insert, a mobile telephone, having the warning system, and a method of fabrication.
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