Each of the four cameras is displayed in a corner of the screen. There is generally a button for each camera which when pressed calls the camera to full screen. You may use anywhere from one to four cameras with a video quad, but the best results are usually obtained when there are at least three cameras in the system. Using only two cameras leaves the bottom half of the screen blank, and wastes monitor space. With a video quad unit, when recording the displayed picture, what you see is what you get.
Multiplexers have two main functions.
They have the ability to display up to 16 camera signals on the screen at once, in a variety of formats. This reduces the number of monitors that may be needed in a given system. They also act as high speed switchers, recording all of the cameras to the video tape, one frame after another in a high speed format. The advantage of this is that upon playback, you can select a particular camera for playback, and watch only that camera, regardless of the camera that was being viewed at the time. If you need a more detailed explanation of the differences between these units, please don't hesitate to e-mail us with your application, and we will be happy to make a recommendation.