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Phone Jack wiring help

334 Views 3 Replies 4 Participants Last post by  diyorpay
Hi all, sorry for the rookie question, see below, part in bold is the question...

I have a total of 5 old phone jack boxes with wiring coming out of them, I want to replace these phone jacks with new ones. All boxes have 1 red wire, 1 green wire, 1 black wire, 1 yellow coming out of each box.

3 of the 5 boxes - all wires were stripped and all wires were wired up accordingly to the colored wire and the same colored terminal (assuming this is the norm), I just replicated this on the new jacks.

1 of the 5 boxes had a middle portion of only the black and yellow wire stripped out and the other two wires attached to nothing and not stripped. The old phone jack had the yellow box wire attached to a red terminal (on back of phone jack) and the black box wire was attached to the green terminal (on the back of the phone jack). Is this right? What is going on here

The last box also had middle portion of only the black and yellow wire stripped out, but no idea what terminal on the jack they were attached to cause the jack was gone, assuming it was the same scenario as bolded above.
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A phone line requires only 2 wires. A cable with 4 (or more) wires can support more than one phone line.

Traditionally, red and green are used for the first line and black and yellow are used for the second line.

Most phones come wired to use the red and green line. If you wanted the phone to connecet to the other line, you'd have to change the wiring of either the phone or the jack.

The funny wiring you found where the black and yellow were attached to the red and green terminal would have allowed an unmodified phone to be plugged in there, but it would have been connected to line 2 (if I followed your description correctly).

The second line might have been used for voice, a fax machine or a dial-up computer modem.
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In the olden days :vs_laugh:, the wires beyond red and green were also used the give a light, as on the famous Princess phone in every bedroom.

Wiring like to like is your best bet and if you get a dial tone, good to go.

Notice however, the jack wiring you may be using. The curly one too. Look carefully at an end. There may be only 2 wires (as in green and red). In that case, a second line would not work if it were a 2 line console phone.

So wherever there's 4 wires that are 'live', today it is likely that 2 lines are being supported.

Another olden days tip :vs_laugh::vs_laugh:: If you're still hooked to a copper service, keep an old wired phone handy (not cordless) for use during a power outage. The current in the red and green is enough to give you dial tone.
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