A telecommunication device has: a projection unit for projecting image information on a projection surface situated outside the telecommunications device, the image information being projected onto the projection surface (i) with the aid of at least one optical element in a projection beam path for sequentially constructing an image, and (ii) for momentarily spatially limiting the projection relative to the total area of the image information on the projection surface; and a detection unit. During projection a movement of the projection surface, e.g., a displacement or a rotation, takes place relative to the projection unit. The detection unit detects the movement of the projection surface with the aid of a reflection signal passing along a detection beam path, the projection beam path and the detection beam path coinciding at least in the area of the at least one optical element.