Electronic surveillance system and transceiver unit therefor
First Claim
1. An electronic surveillance system comprising a plurality of transceiver units at spaced locations within the system, characterized in that each of said transceiver units comprises means for establishing a cycle of operation, for transmitting digital data in turn, to all other units of the system at an exclusive time slot in said cycle of operation, said data identifying the particular unit transmitting data and providing status information, means for recognizing, at all times, a said transmission from any other unit of the system and also identifying a transmission from the immediately preceding unit in said cycle, and performing a said transmission next in turn thereafter, the unit last in said cycle including means for transmitting coded information such that the first unit in said cycle can identify the end of a cycle and recommence, and each said unit comprises means for responding to the failure of any one unit of the system to transmit said data in turn, and for responding to receipt of said status information.
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Abstract
A transceiver unit for an electronic surveillance system is internally coded with an address-number for identification within the system and is adapted to receive input from sensors detecting alarm conditions. The unit is switchable from an idle condition wherein it transmits digital data relevant to its address-number and status but does not recognize input from a sensor, to a primed condition wherein it transmits digital data relevant to its address-number and status information indicating an alarm condition. The unit is able to receive digital data from other similar units sequentially and display information relevant to the identity and status thereof. In a security system a plurality of such units communicate with each other and in turn transmit the digital data to all the other units of the system simultaneously, either by hard wiring thereto, radio link or other transmission medium. An alarm condition detected by one unit is recognized at all other units of the system. Remote switching of a unit from idle to primed by any of the other units is disclosed.
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Citations
13 Claims
- 1. An electronic surveillance system comprising a plurality of transceiver units at spaced locations within the system, characterized in that each of said transceiver units comprises means for establishing a cycle of operation, for transmitting digital data in turn, to all other units of the system at an exclusive time slot in said cycle of operation, said data identifying the particular unit transmitting data and providing status information, means for recognizing, at all times, a said transmission from any other unit of the system and also identifying a transmission from the immediately preceding unit in said cycle, and performing a said transmission next in turn thereafter, the unit last in said cycle including means for transmitting coded information such that the first unit in said cycle can identify the end of a cycle and recommence, and each said unit comprises means for responding to the failure of any one unit of the system to transmit said data in turn, and for responding to receipt of said status information.
- 11. A transceiver unit for an electronic surveillance system, characterized in that, the unit comprises means for frequently and periodically transmitting digital data identifying its address number, means for operating said unit in a primed condition in which said unit is actively connected to one or more alarm condition sensors, and transmits the status of each of said one or more alarm condition sensors and means for switching said unit from said primed condition to an idle condition wherein it is able to transmit digital data relevant to its address-number and status but does not recognize an input from an alarm condition sensor, said transceiver unit also comprising means for receiving digital data sequentially from other similar transceiver units and displaying the address and status of any said units which do not transmit or which are in an alarm condition, said unit being programmable to "listen" continuously through two consecutive phases, a first said phase termed a report phase during which said unit performs, upon initiation, said transmission of digital data relevant to its address-number and status and a second phase termed a command phase during which said unit is adapted to count a predetermined number of timing intervals and is able to receive an instruction by way of digital data to cause said unit to perform some action.
Specification