The I²C bus was invented by Philips Semiconductors (now NXP Semiconductors) in the late 1970’s. It was originally designed as a control bus for linking microcontrollers and peripherals for Philips consumer products. The specification was defined in such a way to allow devices from different vendors to interoperate with simple hardware and software. Early applications for the I²C bus were primarily in consumer products such as PCs, cellular phones, car radios or TV sets but today the I²C bus is being used in a wide variety of applications, even those requiring longer distances spanning a room or building.