Electronic security and surveillance system

Security and surveillance system comprising a central station connected to a plurality of remote installations by means of a transmission medium having a finite information bandwidth wherein:

• a. each remote installation comprises:
• i. a plurality of surveillance equipment associated with a plurality of monitored locations for collecting raw security information including audio, video, and alarm information;
• ii. switching means with a plurality of inputs connected to the surveillance equipment for sampling the security information at its inputs in serial fashion and providing the security information at its output, the switching means being capable of locking onto a particular input in response to an alarm condition at a particular monitored location;
• and
• iii. interface unit transmitter means connected to the output of the switching means for receiving and processing the raw security information including:
• (a) video compressor means for compressing the video information in bandwidth to provide compressed video information;
• (b) alarm decoder means for generating an alarm code from the alarm information in order to identify the particular location of an alarm condition;
• (c) sub-channel modulator which uses a key frequency unique to each remote installation to modulate and thereby sub-channelize the audio information, the compressed video information, and the alarm code to provide processed, sub-channelized security information within a base band frequency spectrum of predetermined size;
• and
• (d) transmitter means including channel modulator to translate in frequency the base band frequency spectrum with its processed, sub-channelized security information into an available downstream channel of the transmission medium;
• and
• b. the central station comprises:
• i. receiver means including channel demodulator connected to the transmission medium for recovering the processed, sub-channelized security information from the available downstream medium channel;
• ii. a plurality of interface unit receivers each associated with a remote installation and connected to the channel demodulator for reprocessing the processed, sub-channelized security information including:
• (a) sub-channel demodulator which uses the key frequency unique to the associated remote installation to recover the audio information, the compressed video information, and the alarm code from the sub-channelized security information within the base band frequency spectrum;
• and
• (b) video expander means for expanding the compressed video information to provide the video information;
• and
• iii. master switching means connected to the interface unit receivers for selecting for display on command particular audio information and video information;
• and
• iv. command unit connected to the master switching means and the interface unit receiver for controlling the master switching means in response to the alarm code.