Modern electronic equipment and information systems, such as digital cameras and computers, rely upon the binary number system to process and communicate information. This is a positional numeric system which uses two as a base, as opposed to the widely understood decimal system which uses the more familiar base ten. The principal advantage of the binary system is that it employs only two different symbols, ie 1 and 0. It is therefore convenient when describing bi-stable or two-state systems with only "on" and "off", or "go" and "no go" states. Transistor-based integrated devices therefore typically accept and output data as short pulses that switch instantaneously between two voltages such as 1volt and 4 volts.