CCTVs, also known as video magnifiers, provide on-the-fly magnification of many types of materials that scanners can't process, including handwritten documents. They can also be used to magnify detailed handiwork, such as sewing or assembling small objects.
Most CCTVs, including the one at the Knox Center, have a bed where the user places the materials to be magnified. This bed can be moved around to change what part of the material is shown on the monitor.
Optelec ClearView+ (stand-alone)
Power. Turns the ClearView on and off.
Viewing Modes and Zoom. Pressing the central button cycles among three modes: black-on-white, white-on-black, and actual colors. Moving the lever on the side of the button to the right changes the zoom from 2.5x to 50x.
Image Conrol button. Pressing and holding one side of the button adjusts the focus.
Autofocus. Pressing this button turns the autofocus feature on and off. Holding the button down for four seconds displays system information; holding it down for four seconds again turns the display off. Holding down the left or right side of the Image control button and pressing the Autofocus button reduces or increases the brightness.