The main circuit board in a computer or electronic device. The motherboard often (but not always) contains the CPU and is usually the board into which all of the other sub assemblies or boards connect. For example, in a keyboard the motherboard may house the CPU, RAM, ROM, and all of the processing “stuff,” while the board containing the A/D and D/A conversion (the audio board) connects to it. There may also be a display or front panel board, and a number of other assemblies (digital I/O board, keyboard, expansion cards, etc.). The exact architecture will vary from device to device, but in general the motherboard is the main board and sort of acts as the “traffic cop” for the rest of the system by controlling everything and routing signals and data to their proper destinations. The motherboard is generally the largest physical board in a device, if for no other reason than to accommodate the connectors for everything that must plug into it, though they usually have the most electronic components as well. Some electronic equipment does not have an obvious motherboard. These are usually older devices where resources were divided among several equal but separate assemblies. In modern manufacturing it is usually more cost effective to put most everything on one main board.