The invention relates to a cellular telephone integration system, comprising an adapter and a mounting device, whereby the adapter incorporates a base body with a seating, whereby the adapter incorporates at least one interface with the cellular telephone. Here, the adapter incorporates a clip, which projects over the seating, in the direction of the seating from one edge of the base body in a clamping position under pretension such that a cellular telephone can be inserted between a free end of the clip and the seating in a clamping position, whereby the cellular telephone in the clamping position between the clip and the seating is secured by the clip pressing on the cellular telephone such that this is held firmly in position in the clamping position, even while the vehicle is in operation.