Abstract: An infra-red detection device comprising an infra-red detection section; a plurality of optical elements arranged to direct infra-red radiation to the infrared detection section; and a masking section arranged to partially mask a first optical element of the plurality of optical elements, such that a first part of the first optical element is masked and a second part of the first optical element is not masked, such that the masking section is arranged to attenuate infra-red radiation directed via the first optical element.

Abstract: Embodiments of the present invention relate to a detector comprising first and second lenses for use with respective first and second sensing means; each lens comprising a plurality of Fresnel facets having respective fields of view adapted such that the fields of view of the first lens are alternately arranged with the fields of view of the second lens such that the fields of view of the first lens are adjacent only to, but do not overlap with, the fields of view of the second lense in a single direction.

Abstract: Embodiments of the present invention relate to a detector comprising first and second lenses for use with respective first and second sensing means; each lens comprising a plurality of Fresnel facets having respective fields of view adapted such that the fields of view of the first lens are alternately arranged with the fields of view of the second lens such that the fields of view of the first lens are adjacent only to, but do not overlap with, the fields of view of the second lense in a single direction

Abstract: Embodiments of the present invention relate to a range reduction detection apparatus that is able to detect blocking of its field of view. Detection of an event, due to movement or intrusion within the field of view, is arranged to start a timer, which will time-out thereby providing an indication of such blocking unless a subsequent event is detected within the time-period.

Abstract: Embodiments of the present invention relate to a detector comprising first and second lenses for use with respective first and second sensing means; each lens comprising a plurality of Fresnel facets having respective fields of view adapted such that the fields of view of the first lens are alternately arranged with the fields of view of the second lens such that the fields of view of the first lens are adjacent only to, but do not overlap with, the fields of view of the second lens in a single direction.

Abstract: Embodiments of the present invention relate to a range reduction detection apparatus that is able to detect blocking of its field of view. Detection of an event, due to movement or intrusion within the field of view, is arranged to start a timer, which will time-out thereby providing an indication of such blocking unless a subsequent event is detected within the time-period.

Abstract: Embodiments of the present invention relate to a detector comprising first and second lenses for use with respective first and second sensing means; each lens comprising a plurality of Fresnel facets having respective fields of view adapted such that the fields of view of the first lens are alternately arranged with the fields of view of the second lens such that the fields of view of the first lens are adjacent only to, but do not over-lap with, the fields of view of the second lens in a single direction.

Abstract: An event detection device comprising a sensing means for generating an output signal in response to the detection of an event, the device comprising a fault monitoring system which comprises: comparator means for comparing the output signal with a threshold signal and for activating a timed sequence processor when the output signal exceeds the threshold signal on a first occasion, the time sequence processor being adapted to activate a fault indicating circuit after a predetermined time interval unless the sensing means generates an output signal in response to the detection of an event on a second occasion within the predetermined time interval.

Abstract: A system for monitoring for integrity of a telephone line connected between a central monitoring station and a subscriber's equipment which comprises a first module for initiating transmission of an identification code from the subscriber's equipment along the telephone line to be monitored to the central monitoring station during an incoming ringing signal; a recognition module response to said transmitted identification code for recognizing the identification code; and a second module for dropping the line after said transmitted identification codes has been recognized and before the line has been picked up.

Abstract: A combined technology event detection device for detection of an event such as movement and/or body temperature, such as an intrusion detection device. The event detection device includes: a passive infrared (PIR) sensor to generate a first output signal in response to detection of an event; a microwave sensor to generate a second output signal in response to detection of an event; a logic device to receive the first and second output signals, which activates an alarm in response thereto; and a fault monitoring system.