Certain aspects of the disclosure relate to providing detailed control channel design for a dynamic selection scheme between normal subframes and special subframes. The first end portion is adapted for connecting to a grommet, and the second end portion is adapted for connecting to another part, such as a second grommet, a nut or the like to form a subassembly of the grommet and the other part. The local master server is coupled to the central master server via a first network and is synchronized to the global master server.