Techniques for supporting communication in a dominant interference scenario are described. A threshold tracking time delay of the tracking circuit is determined. A plurality of bypass paths is also provided in the manifold. Thus, the cells of the airbag are prevented from being trapped by the pillars to thereby enable the smooth deployment of the airbag. The practitioner may modify the proposed prescription and view the resulting placement of the orthodontic objects until a desired result is obtained. The disc changer comprises a disc housing unit, a disc transfer mechanism provided on the upper surface of the disc housing unit, and a disc playback unit.