A comprehensive and searchable network of on-line directories of service providers and a method for a user to use this network is disclosed. The power semiconductor element is mounted on a first surface of the first frame portion. A rotatable joint is formed between the display screen and the casing to allow for adjustment of angular position of the screen with respect to the viewer. The size and location of the domains depend on the antenna directivity of the end-users and on the relative positions of the distant base stations and the base station. The cam includes a resisting end. The oscillation joint assembly is structured and arranged to drivably transmit rotation to the tandem output assembly through the oscillation joint.