Telephone Wiring Mystery

[micky]

I'd be very surprised if what you bought is backwards. I've never seen that Unless you bought the stuff at a dollar store. That's the kind of thing they would sell. (Check out Jay Leno's shopping trips with various mismarked things people send in from dollar stores.)

That said, I never worry about polarity until somthing doesn't work, and it's been 15 or 20 years since something didn't work (that was a trouch tone phone that wouldn't make tones unless it was connected right, or the jack was wrong.)

I suppose if the polarity was reversed between two phones and you held one to your left ear and one to the right, you'd losse a lot of bass. As with stereo speakers. But that hasn't come up.

[micky]

Don't forget that you can only have so many real phones on your phone line. They have a Ringer Equivalency Number of 1, and the maximum sum is 3 or 4. If you go over that number that phone or all the phones won't ring. Modern, phoney phones have RENs like 0.2.

[gfretwell]

That is the real test

You got it right.

[Stormin Mormon]

How many amps for phone, or DSL? AC or DC?

Christopher A. Young Learn more about Jesus

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Nope. It was just a modular extension cord that I could afford to cut in half and bare the wires, allowing me to check color to color with an ammeter.

I installed it, and it, and both DSL modem and the telephone seem to be working fine.

[Stormin Mormon]

A tip o' the hat to you, and that's why they rang.

Christopher A. Young Learn more about Jesus

.

The last intercom I installed used "tip and ring" terminology, that was last May

[gregz]

I know they had them in the 70's, probably 80's. I think I have a conair wall phone in my kitchen, right now.

Greg

[gfretwell]

I think it is something like 20ma that causes the line to go off hook

The line is nominally 48VDC on hook and pulled down around 5-10 off hook.

The max they say they will source is around a half amp but they don't say what voltage that will end up being. I bet you can't really get that much.

[gregz]

I just remembered I had a nice AT&T self lighted phone , that was really nice while it worked. That was a latter model. Good money too.

Greg

[krw]

Even my cell phone has a lighted dial. ;-)

[krw]

Two miles of 26GA wire (one mile from the CO to the house) is around

400ohms, so that's 120mA into a short. 24GA wire would be around 250ohms. Scale from there.

[David Kaye]

"mike" wrote

Black and yellow have also been used for the dial light power on Princess and Trimline phones.

[Stormin Mormon]

So, the guy cut a modular cord in half, and used ammeter to check the wires. I wonder how many amps he had, in the cut cord?

Christopher A. Young Learn more about Jesus

.

I think it is something like 20ma that causes the line to go off hook

The line is nominally 48VDC on hook and pulled down around 5-10 off hook.

The max they say they will source is around a half amp but they don't say what voltage that will end up being. I bet you can't really get that much.

[makolber]

To the op Think about how the modular extension cord that you cut in half was made. Are the two halves now EXACTLY the same or are they mirror images of each other. Mark

[George]

If you are using old wiring. They moved away from quad station wire some time ago.

[George]

The later versions of those were LED and line powered.

[Mark Lloyd]

If you have a 6-wire cable (apparently the only thing the local Lowes sells), the third pair is blue/white.

I've also seen 3-pair cable that had green, blue, and orange (solid/stripe) pairs. Also 3-wire cable (red/green/yellow, no black).

[Mark Lloyd]

I got a lighted-dial phone in my first apartment (about 1980), however it was powered by the phone line and lit only during a call.

Someone had left an old transformer connected to the yellow/black wires.

[Mark Lloyd]

[snip]

I seem to remember something about an additional wire (yellow?) used for ring control on some party lines.

[Mark Lloyd]

I checked the line here, about 10 years ago. I got 50VDC when on hook, and 6VDC when off.

[Mark Lloyd]

[snip]

How do you get 4? If you had flat cable, there would be only 2 ways. With individual wires it's 4! (4*3*2*1 = 24).

6! (6*5*4*3*2*1 = 720) for 6-wire cable.

I suppose they decided it'd cost too much to include a bridge rectifier.