PCT No. PCT/EP97/00643 Sec. 371 Date Aug. 7, 1998 Sec. 102(e) Date Aug. 7, 1998 PCT Filed Feb. 12, 1997 PCT Pub. No. WO97/29499 PCT Pub. Date Aug. 14, 1997An apparatus for protecting a keyboard and includes a sound transformer placed in the keyboard and a sound receiver placed outside the keyboard to receive a signal radiated from the sound transformer. The signal is then analyzed to determine if the power of the radiated signal has dropped below a threshold value, indicating potential tampering of the keyboard.
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