At any given point in time, a circuit can only be in one of two states: either "on" or "off", i.e. “close” or “open”. Computer communications and storage, at their most basic level, must be built upon sequences of "on and off" signals or values. While there are numerous ways of transmitting and storing on and off signals and values, whether via voltage, fiber-optic light, microscopic indentations on disks or magnetism the "on and off" language remains the same.