A method includes reserving, at a wireless local area network controller, a first reserved communication channel from a plurality of communication channels available for use in a wireless network. A light source projects an incident light into the prism through a second surface of the prism. The session layout module generates a selection configuration for selecting the type of interaction with the client server system. , in a standby mode, a switch is turned off, and a pseudo-ground line is charged with a leak current of the internal circuit to raise a potential thereof.