| 摘要 |
<p>Apparatus, for example postage metering apparatus is described as being provided with tamper detection means. The tamper detection means may comprise an electrically conductive or resistive first layer (15) extending between a wall of a secure housing (10) and components critical in the proper functioning of the apparatus. An indicator may include a second electrically conductive layer (16) extending adjacent and electrically isolated from the first layer and means responsive to completion of an electrical path between the layers or means responsive to change in resistance of the resistive layer. In an alternative construction, the tamper detection means includes a sealed enclosed space (24) containing gaseous substance at a pressure above ambient air pressure and means (23) responsive to a decrease in the pressure in the space to permit a mechanical interposer (20) to engage an operable mechanical element (13) of the apparatus to inhibit operation thereof. <IMAGE></p> |
