Abstract: A display button of a push-button switch according to the invention includes a central design display portion and angular display portions, which serve for illumination, arranged on the display surface of a push-button, with a display of a color contrasting with that of the background. Displays having a variety of colors and modes can be presented by selectively illuminating and displaying both display portions.

Abstract: Adjacent memory layers of a multi-layered integrated device as optically coupled, so that data written on one layer can be copied onto its adjacent layers through the optical coupling.

Abstract: An address management system includes a central processing unit (CPU) and an address management unit arranged between a direct memory device (DMA) and a main memory unit to control memory access from the CPU and DMA. Segment registers for address expansion are provided in the CPU and DMA, respectively. The address management unit includes a conversion table for converting logical address data and segment data and segment data from the CPU and DMA into a corresponding physical address data, and the conversion table includes a bit position for detecting an address error and a control bit for selecting a memory access to a local memory or a shared memory.