RJ11 is a physical interface often used for terminating telephone wires. It is probably the most familiar of the registered jacks, being used for single line POTS telephone jacks in most homes across the world. Cables sold as RJ11 are nearly always 6P4C (six position, four conductor), with four wires running to a central junction box. Two of its six possible contact positions connect tip and ring and the other two conductors are then unused. 6P2C and 6P6C can also be found in stores.