A media access controller is configured with a header creator circuit. In the interlayer grounding conductor layer opposed to the signal wiring conductor is provided a conductive layer non-forming portion so as to be located in a region directly above the ball-shaped signal terminal mounting pad. Second optical signals may be received from the optical fibers and converted to electrical signals for use by the CMOS chip. The frame 2 is made of magnetic metal, and the one-touch fixing member is made of magnets 31. The communication system determines a signal strength of a signal received from a user of the communication resource and, based on the signal strength determination, assigns the user one or more of the communication channels that are then available. The cache payback parameter is tracked concurrently with the performance of a plurality of cacheable operations on a memory, and is used to determine the effectiveness, or potential payback, of caching in a particular implementation or environment.