Surveillance system

Claim 1

A remote survelllance system, including a plurality of surveyed stations and a common control station, first programmable means disposed one at each said surveyed station and second programmable means disposed at the control station, said first and second programmable means being adapted to effect communication between each said surveyed station and the control station via a telephone line, one or more detectors disposed at each said surveyed station, video means disposed at each said surveyed station, data compressors one at each surveyed station and adapted to compress video signals to a form suitable for transmission over a said telephone line to the control station, and a data expander provided at the control station and adapted to receive video signals from compressed data received from a surveyed station, said data compression and expansion being effected via said first and second programmable means respectively, the arrangement being such that activation of a said detector initiates telephone communication between the corresponding surveyed station and the control station whereby to transmit video information to the control station, wherein means are provided for transmitting an identifier code from a surveyed station to the control station at the commencement of communication therebetween, and wherein said control station has data compressor means for transmitting video signals to one or more said surveyed stations, said surveyed stations having data expander means for removing said video data.