Abstract: A card reader operated in proximity to secured area control point including an operating system therein to provide multiple operating modes. The card reader is operable to provide access to a secured area by entry of an identification code, which is read by the card reader, or entered to the keyboard. The user will be granted access to the controlled area when the user access requested corresponds to the level of access provided by the identification codes presented. The card reader has a programming mode, to allow a station manager to program the reader for presenting a programming code. The card reader system also has a degraded mode of operation, which allows user access after power fail and reader restart. A keypad having an interchangeable faceplate is used for all three modes of operation to provide communication and programming with the reader by the system user.

Abstract: An optically-based coded card identification system is provided in which a card having an access code defined by adjacent differently-polarized elements used in a transmissive or reflective mode is interrogated through a deep red or near infrared transmissive filter as the card is pased by a source of illumination. The use of polarization coupled with the adjacency of the differently-polarized elements makes the code nearly invisible to the naked eye, with the code being made more invisible due to the low visible light transmission of the filter on the face of the card. In one embodiment, coding for the cards is provided by overlying layers of material polarized in different directions, with portions of the layers provided with offset apertures so that light through an aperture in one layer is polaried by an unapertured portion of the adjacent layer immediately thereunder.

Abstract: A security system continuously monitoring a plurality of spatially diverse events which are reportable to a central monitoring facility, the system including a controller for sequencing the performance of reporting and monitoring tasks according to the requirements of the events. The system also performs the tasks according to a predetermined priority, in particular, alarm message queuing. In addition, alarm conditions and system operation are verified by specified communication procedures and redundancies. Furthermore, system communications capabilities include keyboard entry and output display and an interrupt facility.

Abstract: A multi-zone alarm system operative with a two-wire alarm loop and having a simple network at each alarm sensor for providing a coded signal indicative of sensor identity and relatively simple circuitry at a central location for interrogation of the remote sensors and determination of those sensors providing an alarm signal.

Abstract: Zone indication is provided for a facility monitoring and control system by providing the system's sensors and control unit with counters which are simultaneously incremented with clock pulses delivered to the sensors via the multi-wire interconnect cable from the system's control unit. Each sensor output circuit has enabling circuitry connected, as with jumper pins, to a counter output corresponding to a predetermined number or count, and this number or count identifies the sensor. In one embodiment, each sensor output is enabled only during the occurrence of the corresponding count or number from its counter as the counters are incremented through their cycle. When the sensors are used to sense alarm conditions, the sensor sending an alarm signal is identified when an alarm condition signal exists simultaneously with a particular count from the counter at the control unit, with the particular count indicating which sensor is sending the alarm signal.

Abstract: A multi-zone alarm system operative with a two-wire alarm loop and having a simple network at each alarm sensor for providing a coded signal indicative of sensor identity and relatively simple circuitry at a central location for interrogation of the remote sensors and determination of those sensors providing an alarm signal.

Abstract: A multi-zone alarm system operative with a two-wire alarm loop and having a simple network at each alarm sensor for providing a coded signal indicative of sensor identity and relatively simple circuitry at a central location for interrogation of the remote sensors and determination of those sensors providing an alarm signal.