Need to split your phone line? Or connect two phone cords together to make a longer one? These RJ11 converters are handy around the home and office. Various versions available to match your needs.
These are 6 position and 4 or 2 conductor (6P4C or 6P2C) modular jacks and plugs. See the link for information about jack/plug configuration.
Phone line adapters and gender changers.