But they can be very tiring to use, especially when a high magnification is needed for reading. Some are portable, some can be linked to a computer, others can be used with a typewriter. With this type of equipment, the user sits comfortably in front of the set and the material to be read is displayed on a screen in enlarged print, either black on a white ground or as a white print on a black ground, though some models have other colour options. A camera is mounted vertically above a moveable platform on which the reading matter is placed. The user moves the platform to and fro so that the camera scans the print.
Some models have a small hand-held camera which the user moves along the line of text.
Television readers require the user to have a television set tuned into a spare channel. A hand-held scanner is connected to a box into which the TV aerial is plugged. The scanner is run over the material to be read, which then appears, greatly enlarged, on the television screen. One portable version is now available which has its own 7 inch monitor and rechargeable battery. Another system also uses a television set as a monitor but the camera is mounted on an adjustable arm so it can be pointed in any direction.