Abstract: The connection system connects a block (1) to a plate (3), each of which has a compressed air orifice. The block has a slideway for receiving a square section projecting portion on the plate, e.g. by sliding in a direction F2. Strips (6) are then slid into the assembly along a perpendicular direction F1 to lock the assembly. This system enables blocks to be removed from fixed metal pipework (5) without having to loosen the pipework. Also, because of the square section of the projecting portion, the block can be slid onto the plate in any of four different orientations, which can help in placing operator controls or instruments in more convenient positions.