High Quality Content by WIKIPEDIA articles! I²C ("i-squared cee" or "i-two cee"; Inter-Integrated Circuit; generically referred to as "two-wire interface") is a multi-master serial single-ended computer bus invented by Philips that is used to attach low-speed peripherals to a motherboard, embedded system, cellphone, or other electronic device. Since the mid 1990s, several competitors (e.g. Siemens AG (later Infineon Technologies AG), NEC, Texas Instruments, STMicroelectronics (formerly SGS-Thomson), Motorola (later Freescale), Intersil, etc.) brought I²C products on the market, which are fully compatible with the NXP (formerly Philips's semiconductor division) I²C-system. As of October 10, 2006, no licensing fees are required to implement the I²C protocol. However, fees are still required to obtain I²C slave addresses allocated by NXP.