A cavity 22 in an injection molding assembly includes a lower mold insert 21 for shaping a lens convex surface and an upper mold insert 20 for shaping a lens concave surface. The current flowing when a test voltage is applied between a pair of electrodes is measured before an electrolyte is placed between the electrodes. A tensioning device may be provided along one of said frame sides for causing tensioning of localized regions in said mesh after said mesh is wetted with water. A time difference between the first and second signal transit times at the reference point is calculated to determine the clock drift. Other embodiments are described and claimed. By acquiring the information on the latest service category table, a session connection with only the device providing the desired service is established so that an optimized session connection establishing process can be performed and a total network capacity can be efficiently managed.