telephone wiring questions

Are RJ11 and RJ14 modular plugs the same size?

Do they physically fit the same jack?

The RJ14 jack can accommodate six conductors. If you use a single line, four conductor phone cord (assumes a four conductor plug) into an RJ14 jack, does it work OK (assumes the device the jack is in is a single line phone?

Will a two line, four conductor phone cord (assumes a four conductor plug) work OK in an RJ14 jack (assumes the device the jack is in is a two line phone)?

Reply to
rb
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An RJ11 plug will fit and work correctly in an RJ14 jack.

Reply to
Marilyn & Bob

Yes.

Yes.

So can the RJ11 jack.

Yes. That assumes the wiring is correct.

Yes.

Reply to
Jim Redelfs

Probably.

I see the 6P6C (6-conductor) jacks called RJ12. Those are the same size as 6P4C ones (RJ11). A RJ11 plug will fit into a RJ12 jack, with the 4 conductors automatically making contact with pins 2-5. An RJ12 plug will work, except than pins 1 & 6 will not be connected. An RJ12 crimping tool will work on RJ11 plugs (I think) but an RJ11 crimping tool will NOT work on RJ12 plugs.

Reply to
Mark Lloyd

It will accept the PLUG but will not make contact with the extra 2 wires.

Reply to
Mark Lloyd

OK. Many thanks.

Seems like the determining factor is how the device jacks are wired and configured. My sense of how this stuff works is that the jacks ignore wires that are not there or that are not used by the devices they're in, assuming the wall jacks are wired right to start with.

Reply to
rb

Not to worry, assuming that the wiring up of the jack was correct. The two, innermost, copper connections is what is making for Line 1 so whether it's a four conductor plug or a six, or eight, as long as the middle two make you have a phone. The jack can be 2, 4, 6, or 8 copper pins and your single line phone plug work. You can't reverse that though and try and put a 6 wire or 8 wire plug in a RJ11 Jack, but then you knew that already. Polarity today isn't much an issue either but the line one colors are red & green wires.

Remember though that each phone jack has 46 - 52 Volts DC on it when the line is off hook and even more stimulating if you happen to get a call then there is from 90-105 Volts AC pulsating through those connectors at around

20Hz to ring your phone. Been there and tasted it .. .not a good taste :) so if you wire up your own jacks or mess around with them take care that no one calls during the time you are touching the connectors.

Reply to
Gary KW4Z

None of the modular plugs have an RJ designation until they are wired for a specific telephone application.

All 6 position jacks are the same physical size, the number of contacts determine which applications it can be wired for.

For RJ11, the minimum is 2 contacts. For RJ12, RJ13, and RJ14, the minimum is 4 contacts. For RJ25, the minimum is 6 contacts.

RJ11 is used for a single line, pins 3/4. RJ14 is used for two lines, pins 3/4, and 2/5. RJ25 is used for three lines, pins 3/4, 2/5, and 1/6.

RJ12 and RJ13 are used for a single line, pins 3/4, with A-lead control pins 2/5.

RJ12 and RJ13 are not commonly seen, as the 1A2 key systems that they were used with are largely extinct. Both RJ12 and RJ13 use the second pair (pins 2/5) for the A lead control, which conflicts with RJ14, which uses that pair for the second line. A device wired for RJ12 or RJ13 will short the second line when plugged into a jack wired RJ14.

The difference between RJ12 and RJ13 is that RJ12 bridges the line before the key system, and RJ13 bridges the line after the key system.

Reply to
Bob Vaughan

Also, the jacks will accept smaller plugs. The shape of the jack and plug cause the plug to be centered within the jack, making contact with the central wires.

I noticed that Lowe's only sells 6P6C phone plugs (all 6 connections present). These work fine with existing 6P4C (most RJ11) or 6P2C (one pair only) jacks. Mark Lloyd

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Reply to
Mark Lloyd

True, although the jacks used for telephones are really 6-wire size with the outer 2 wires missing. These accept 6-wire plugs fine, connecting to wires 2-5.

4-wire plugs and jacks are smaller, and are used for wired telephone handsets.

You can probably disconnect the wires outside while working on the connections.

Mark Lloyd

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"The government of the United States is not, in any sense, founded on the Christian religion."

-- George Washington

Reply to
Mark Lloyd

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