A portable device (1) with at least one optical output device (2) for displaying at least process data of a machine, a robot or a technical process, with at least one input device (3) for at least intervening in the operating functions of the device (1) and/or for operating the machine or robot or technical process, and having a safety switch device (12) for preventing the output of undesirable, unintended control commands for the machine, robot or technical process. The output devices (2) and input devices (3) are connected to a control device (14), which is accommodated in a housing (7) that is unbreakable as far as possible and at least one communication interface (17) is provided to an external control device disposed at a distance away. Several of the input and output devices (2, 3) are functionally combined by means of a touch-sensitive screen (4) in the form of a touch-screen (5) and the touch-sensitive screen (4) extends across substantial regions of the surface of the housing (7).