More about Rj 11 connectors

What are the use Rj11 connectors ? I had found Rj11 connector module with 4 pin 6 pin etc. ,what are the use of these different number of pin contained Rj11 connector module ?

Here are the most common........................

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Wiring Instructions and Diagrams for RJ11 and RJ45 Jacks

All RJ-11 connectors have 6 pins, however usually only 2 or 4 are utilized. RJ-11 connector wiring comes in two standard varieties: untwisted (flat-satin cable) and Unshielded Twisted Pair (UTP). In most cases 2 of the conductors are used for the telephone signal and the other 2 are routed to the junction box unused. Sometimes the extra conductors are pressed into service for a variety of special reasons, for example preventing a pulse-dial telephone from ringing the extension phone bells (an 'anti-tinkle' circuit), as a ground for selective ringers, powering an L.E.D. ring-indicator operating off the ringer signal, etc.

The reason for the 6 pins is that the same type of connectors can to be used with multiple line phones: 2-line phones (4 wires - RJ14)and 3-line phones (6 wires - RJ25). All topologies use the same RJ-11 jack and connector.

You can find more information in RJ-11 and in RJ11 Telephone Connector Pinout - AllPinouts