A wireless communication system having a base unit and a plurality of remote transceiver units utilizes a dynamic time slot assignment scheme for channel access. 3-2 mm and a Shore D hardness of 40-55, and the JIS-C hardness at the cover surface is not greater than the JIS-C hardness at the core surface. The surface lighting devices include a voltage step-up circuit that converts a DC voltage produced by the thermoelectric power generation unit into a higher-level DC voltage. However, relationships between the components are created such that the data and functional dependencies form an acyclic graph. Optionally, pages of main store are saved and restored from NVRAM during a power-down, power-up sequence of events.