Abstract: A security and surveillance system having a central monitoring station connected to a plurality of remote installations or subscribers by a transmission medium having a finite bandwidth. Each remote installation includes a plurality of surveillance equipment, including video, audio, and alarm signals, associated with a plurality of monitored locations. The security information collected by the surveillance equipment is serially sampled by a switcher which provides that information to an interface unit transmitter. The interface unit transmitter compresses the video information and decodes the alarm information and then using a key frequency and single side band modulation techniques modulates and sub-channelizes the processed security information into a frequency spectrum. The sub-channelized security information is translated in frequency and transmitted on the transmission medium.