A registered jack (RJ) is a standardized physical interface for connecting telecommunications equipment (commonly, a telephone jack) or computer networking equipment. The standard designs for these connectors and their wiring are named RJ11 and RJ45. The physical connectors that registered jacks use are of the modular connector type cat5e, twisted pair, 350 Mhz, RJ45 crossover. RJ11 uses a 6 pin 2 conductor (6P2C) modular plug and jack. The six-position plug and jack commonly used for telephone line connections may be used for RJ11.The RJ11 standard dictates a 2-wire connection and RJ45 is also used quite commonly to refer to any 8P8C modular connector.