Quads and Multiplexers

This chapter discusses quad and multiplexer, which displays all of the images from many cameras onto a single split-screen monitor simultaneously. The multiplexer and integrated multiplexer–recorder (DVR) has become an important part of the video surveillance hardware. It is a powerful tool, which is capable of combining many video images onto one multi-screen display, thereby reducing the number of monitors required to view the cameras in the system. It can call up camera images showing motion in the scene and also provides the capability to prioritize incoming alarm signals from external sensors with the video motion detection (VMD) alarms. In an analog network, the multiplexer can send the video images and camera identification signals to a video cassette recorder (VCR) or digital video recorder (DVR) for proper synchronization on recording and playback to the multiplexer. In a digital network, it can transmit the compressed images over digital networks to monitors and recorders to remote locations for remote site monitoring. The simplex, duplex/full duplex, and triplex types are available to provide a multiplexer solution to most applications.