RJ14 Jack Within the RJ (Registered Jack) standard , the RJ14 is the 6P4C version of the wall- and baseboard-mounted telephone jacks installed in residences. Compare RJ11 (6P2C), RJ12 (6P6C), RJ13 (6P4C), RJ14 (6P4C), RJ18 (6P6C) and RJ25 (6P6C).