abbreviation for thin film transistor this tft display is a special form of a lcd picture screen whereby thin film transistors designationally activate and deactivate electrical fields for the polarization of the anisotropic liquid of the lcd elements with the assistance of tft technology a high resolution picture is achieved in view of luminance color and sharpness a touch screen unit 34 is provided for inputting data into the control panel 16 the touch screen unit 34 being connected via a controller 32 to the communication interface com 1 the touch screen unit 34 is mechanically connected to the display 20 when an operator touches a touch sensitive actuation field of the unit 34 whereby the actuation field coincides with a display field displayed by the display 20 then a switch signal is communicated to the personal computer 22 the personal computer 22 activates a program part on the basis of this switch signal as a result whereof a menu control or respectively the input of acknowledgment signals numbers and text elements is realized as known in and of itself the device controller 12 is connected to the communication interface com 2 via the data bus 14 fig4 shows the structure of a display on the display unit 20 a plurality of display fields are indicated in the upper line 36 these containing text information and graphic information the various display fields u201c setup u201d through u201c off u201d serve the purpose of user prompting by touching one of these display fields a switch pulse.