Quads are also able to have alarms bring one camera up full screen. Some quads will allow you to zoom in on one camera on playback. A quad is priced right in the middle of the three. Multiplexers A multiplexer offers the best of both worlds. It is possible to view all the cameras on the screen at the same time, but the image is actually recorded full screen.
Multiplexers are available in sizes from four to sixteen cameras.
A multiplexer records each frame full screen and switches between cameras after each frame. To view four cameras at a time the multiplexer will put the frames of only those cameras into the corners like a quad but the images will have been recorded full screen for better resolution. It is also possible to watch only one camera on the monitor while allowing the rest of the cameras to record for any length of time. This can be an important decision to make while designing a system from the start. While black and white cameras typically will have better resolution specifications, we as humans can gather more information when we see things in color.