Man-machine interface (2) for a ISO-data bus (10) to be controlled or to be controlled, agricultural implement (9), with a screen (4) and having a plurality of soft-input keys (5, 6), which depending perform different functions from an associated display of the screen (4), wherein the soft-input keys (5, 6) are constructed as hardware keys or parts of the designed as a touch screen display (4), said first soft-input keys (5) corresponding functions are pre-assigned control side, whereas second soft-input keys (6) are freely assignable with corresponding functions. At least one of the second soft-input key (6) is to be controlled of the adjustment of an operating parameter or to be controlled implement (9) in such a way programmed with a function that, when tip-like actuation of the respective second soft-input key (6) of the corresponding operating para-meters in a defined control range in a first displacement direction is adjustable, and that in permanent operation the respective second soft-input key (6), the corresponding operating parameter can be adjusted within the defined control range in a second, opposite actuating direction.
