1. A mobile, compact personal communicator including a data processing system and a communication device for performing a wide variety of data processing and communication functions comprising: a casing of a size adapted to be held in the hand of a user; a touchscreen display mounted on said casing and including a liquid crystal display (LCD) coupled with a touch sensitive overlay; first and second selectively actuated push buttons mounted on said casing; a cellular phone mounted on said casing and including a speaker having adjustable volume; speaker volume control means connected to said first and second buttons and to said speaker for increasing and decreasing said volume of said speaker in response to selective actuation of said first and second buttons respectively; processing means mounted in said casing, said processing means including screen management means for painting different screens on said display device with contrast control means; and said contrast control means connected to said LCD for controlling contrast of said LCD, said contrast control means comprising: selectively actuated first means in a screen for switching said communicator into a contrast control mode of operation and converting the first and second buttons from speaker volume control to contrast control of the display in response to said first means being actuated, second means, operative during said contrast mode of operation, for increasing the contrast of said LCD in response to said first push button being actuated, and third means, operative during said contrast mode of operation, for decreasing the contrast of said LCD in response to said second push button being actuated.