A family of plugs and sockets used with registered jack (RJ) twisted pair cables. They are defined by the number of positions on the connector that can hold a wire contact and the actual number of contacts. For example, a 6P2C connector means six positions and two contacts (two wires); however, they do not define the purpose of the wires. Common types are 6P4C, 6P2C and 8P8C.
Telephone and Ethernet
The most common uses of modular connectors are for plugging a telephone into the wall outlet (RJ-11), as well as the cable that connects the handset with the phone. They are also the plugs and sockets of RJ-45 Ethernet cables. See RJ-11
The 8P8C plug is an RJ-45 Ethernet connector, while the 6P2C and 6P4C plugs are used for telephone handsets and RJ-11 telephone connections.