A system for testing a mechanical input device of a wireless telecommunication device is provided, where the system comprises a pressure air regulator (100) comprising: a receive unit (102) comprising an inlet aperture (106) and a first contact surface (136) with at least one exit aperture (110) connected to the inlet aperture (106); a distribution unit (104) rotatably pivoted relative to the receive unit (102), the distribution unit (104) comprising a second contact surface (138), which contacts the first contact surface (136) and comprises at least two entrance apertures (114A, 114B) located at a rotational trajectory (112) of the at least one exit aperture (110). The distribution unit (104) further comprises at least two distribution apertures (116A, 116B), each connected to an entrance aperture (114A, 114B), thus providing pressure air when the entrance aperture (114A, 114B) overlaps with the exit aperture (110).