| 摘要 |
In a keypad for an ATM or the like, in addition to mechanical keys (14) which when operated press areas (24) on a pressure sensitive layer (22) against a backing plate (32), and thereby close a corresponding normally-open switch (S), additional areas (26) are arranged as normally-closed switches A, with pressure applied by protrusions (36) on the backing plate (32). If the backing plate is removed, the switches A open, and the change is sensed by a monitoring circuit (48).
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