An IO Module is a device that acts as the connective bridge between a computer system at one end and an I/O or peripheral device of some kind at the other, such as a printer, webcam or scanner. It allows for communication between a computer system and a peripheral device. Some examples of peripheral devices include graphics cards, image scanners, digital cameras, speakers and microphones. The IO module usually includes analog channels, digital channels, or a combination of both. Analog inputs can detect various signals including frequency, voltage, or current. Digital inputs and outputs are used for low-level on-off signals.