Editing Registered jack (section)

==RJ11, RJ14, RJ25 wiring {{anchor|RJ11|RJ14|RJ25}} ==
<!-- [[RJ11]], [[RJ14]], and [[RJ25]] redirect here. -->

All of these registered jacks are described as containing a number of potential [[Electrical connector|contact]] positions and the actual number of contacts installed within these positions. RJ11, RJ14, and RJ25 all use the same six-position [[modular connector]], thus are physically identical except for the different number of contacts (two, four and six respectively) allowing connections for one, two, or three telephone lines respectively.

Cords connecting to an RJ11 interface require a 6P2C connector. Nevertheless, cords sold as RJ11 often use 6P4C connectors (six position, four conductor) with four wires. Two of the six possible contact positions connect tip and ring, and the other two conductors are unused. RJ11 is commonly used to connect [[DSL modem]]s to the customer line.{{cn|date=September 2024}}

The conductors other than the two central tip and ring conductors are in practice variously used for a second or third telephone line, a [[Ground (electricity)|ground]] for [[Party line (telephony)|selective ringers]], low-voltage power for a [[Rotary dial|dial]] light, or for anti-tinkle circuitry to prevent [[pulse dialing]] phones from sounding the bell on other extensions.

===Pinout===
The pins of the 6P6C connector are numbered 1 to 6, counting left to right when holding the connector tab side down with the opening for the cable facing the viewer.
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{{Registered jack}}

===Provisioning of power===
Some telephones such as the Western Electric [[Princess telephone|Princess]] and [[Trimline telephone]] models require additional power (~6 V AC) for operation of the incandescent dial light. This power is delivered to the telephone set from a transformer by the second wire pair (pins 2 and 5) of the 6P4C connector.