Network access apparatus includes a slave unit, including a plurality of subscriber ports adapted to be linked to respective subscriber lines, and a multiplexer for multiplexing among the ports. The system further uses a tomosynthesis arrangement that maintains the focus of an anti-scatter grid on the x-ray source and also maintains the field of view of the x-ray receptor. When a user issues a request to switch an IP broadcasting channel from an IP broadcasting terminal, a query message including the requested IP broadcasting channel identifier is transmitted to a management apparatus. The example method includes determining client compatibility with the viewer and an associated server in the background at a client device executing the client browser while the temporary view is displayed at the client browser. An inert gas is supplied to the wafer from the plurality of blowing apertures which is moved by rotation or turn round of the baffle by using the rotation motor. The frame member includes a first lower beam member, a second lower beam member, an upper beam member, and a plurality of truss members securing the first and second lower beam members and the upper beam member together in a fixed relationship.