With a security device according to the present invention, contact positions of a printed board and those of a casing are electrically connected, and a state in which the contact positions are separated is electrically detected, so that the moment at which the electronic equipment is disassembled can be detected, and with this feature, security for electronic equipment can be insured with simple configuration.

A proximity sensor is provided with a means for sensing an attempt to tamper with the normal operation of a proximity sensor. An Eddy current killed oscillator is used to sense the presence of an undulating magnetic field provided by a coil and a monolithic timing circuit that periodically energizes and deenergizes the coil. A sensing coil is association with an Eddy current killed oscillator to provide an output signal that undulates in response to the undulations of the magnetic field provided by the stationary coil. If the output signal from the Eddy current killed oscillator changes states at a sufficient frequency to continually refresh a retriggerable resettable multivibrator, an output from the multivibrator will remain in a high condition and represent the coincident positions of the zones proximate the output coil and sensing coil. If, on the other hand, an attempt is made to tamper with the sensor by placing a metallic object near the sensing coil, the constant output from the Eddy current killed oscillator will fail to trigger the multivibrator at a sufficient frequency to maintain the high status of its Q output. In addition, the outputs from the Eddy current killed oscillator and the multivibrator are combined to determine that a tamper attempt has been made.

An alarm system includes a housing that substantially encloses a plurality of sensors and an alarm-signal generator. The housing has a thin profile and may be mountable in various locations, such as on a window surface. The thin profile of the housing allows the alarm system to be attached to the surface of a first window and capable of being located between the first window surface and a second window surface upon relative motion between the first window surface and the second window surface.

A computer cabinet tamper detection system includes a switch that is responsive to the chassis being opened to expose the electronic hardware and an auxiliary state element that changes state in response to the switch. A reporting program runs on the hardware to poll the state of the auxiliary state element when the computer is operational to provide notification regarding a safe or unsafe condition of the chassis. This allows the computer operator and the organization to take steps to contain any damage associated with the possible prejudicing of the computer's security.

A door system has a plurality of doors coupled to communication lines which interconnect the doors. The doors have a first outer face having an opening therein and a second outer face spaced a predetermined distance apart from the first outer face. A void is located between the first and second outer face and is sized to receive at least a portion of an integrated door unit. A wiring harness is located between the first and second outer faces. The wiring harness has a connector coupled thereto. The wiring harness is coupled to the integrated door unit. A sensor is coupled to the integrated door unit. To communicate, the integrated door units have a memory storing an address, and a data map. The integrated door units form output data words using the address and the data map.