Yellow wire in antique telephone?

Othersider

Gawd
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Jan 28, 2005
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I have an old black bakelite rotary phone (probably circa late 60s/early 70s). The handset is wired to the base (no connectors). A cable comes out of the base. The wall connector was long ago torn off.

There are 3 very fine insulated wires. Red, green, yellow.

Connecting the red and green to the red and green in current wiring makes it work. I can dial, talk, and hear perfectly on it.

What it doesn't do is ring. Obviously I suspect the yellow wire has something to do with this. I tried connecting it to the red as well; no effect. Is it just that modern phone switches don't provide enough voltage to operate the mechanical ringers?

Worst case, I'll have to end up getting an external powered ringer for it, but if anyone has a better solution, I'd like to know.
 

Duster

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i don't know how telephone ringing works but you could test the wire to see what kind of signal u get from the wires while it rings then you could see what kind of signal u need to make it ring.... then build a small circuit to build...

just a thought


 

jpmkm

That Ain't Mayo On My Lip...
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How many other phones do you have on your line? Back in the day most houses only had one, maybe two phones, so the ring current provided by the telco was sufficient to ring those big mechanical ringers. Today's electronic phones don't require nearly as much current to ring, so that's why we can have so many on one line. However, if you have a lot of phones already, there might not be enough current to ring those and the mechanical ringer in that old phone. Or maybe I'm just talking out my ass and it actually does have something to do with the yellow wire. :)
 
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There should be a black wire, too.

Telco->yellow wire->ringer electromagnet->black wire->telco. Gotta have the whole circuit.
 

ravenc

Weaksauce
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Oct 17, 2004
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look up some of the old phreaking saites they can explain better then i can

christmas colors (red and green) are the only ones you really need

if i remember black was used in payphones for money deposit or return signal
 

Othersider

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HeThatKnows said:
There should be a black wire, too.

Telco->yellow wire->ringer electromagnet->black wire->telco. Gotta have the whole circuit.

Makes sense; maybe I need to strip a little more to find the black wire.

Though if I do, that means it won't work, as modern RJ11 wiring uses yellow/black for the second line. :(
 

SarverSystems

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Here's a bit of useless lknowledge.

REN # (listed on the bottom/back of most phones: Ringer Equivelency Number. The higher the number, the more power needed to make it ring.
 
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you can use a modern cap... they are just saying that the old fassion caps are huge (they are, because they are made out of paper and stuff). so just get a high voltage rated cap from digikey and youll be all set.
 

Mr Lee

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The yellow wire has nothing to do with the ringer. Back in the 60's and 70's it may have been used as a ground, but today it is no longer used. From your discription of the phone, I think you have an old model 500 set. You will have to remove the case and check for loose or broken wires. If you can't see anything wrong with the wiring you probably have a bad ringer coil. The connections will depend on which model you have.

Model Ringer Wire 425A Network
500A/B Black G
Red K
Slate E
Slate-Red E

4228A or 425E Network
500C/D Black G
Red L2
Slate K
Slate-Red A
 

agent420

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^^^ What he said.


The yellow and black wires (also called the Halloween Pair) were never used for standard telelphone service. Phones that offered 2-line service would use the second pair for the additional line.

Modern telephone service still provides the correct ring signal, and the odds are that all the other phones in your house are of the electronic type that use virtually no ringing current. My bet is there is something wrong with the phone itself. Those old phones are very well built, the cockroaches will be using them to call their buddies after WWIII, so it's probably a bad connection inside somewhere.

Although many phones today only have the red and green wires (aka the Christmas Pair), it was very common for standard phones to have all four (r,g,bk,y). Don't know why, perhaps the same reason all network cable has 8 conductors when it really only uses 4 (until the recent gbit anyway).

btw, not sure what the uk does, but here in the us the term 'ring' wire refers to the plug the operators and telco used; it has nothing to do with the ringer. Tip & Ring faq

A little off topic, check out Sparkfun's portable rotary telephone project. They also have a ringer cicruit posted.

[edit]

Looking back at your original post, I'm surprised by no mention of the black wire - I think if you inspect the cable more thoroughly you might find there's a black wire in there... But no matter anyway, it's not used.

[edit 2]

Here is another more technical link regarding telephone wiring, circuitry and operation. A good read for geeks ;)
 
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agent420 said:
^^^ What he said.


The yellow and black wires (also called the Halloween Pair) were never used for standard telelphone service. Phones that offered 2-line service would use the second pair for the additional line.

Modern telephone service still provides the correct ring signal, and the odds are that all the other phones in your house are of the electronic type that use virtually no ringing current. My bet is there is something wrong with the phone itself. Those old phones are very well built, the cockroaches will be using them to call their buddies after WWIII, so it's probably a bad connection inside somewhere.

Although many phones today only have the red and green wires (aka the Christmas Pair), it was very common for standard phones to have all four (r,g,bk,y). Don't know why, perhaps the same reason all network cable has 8 conductors when it really only uses 4 (until the recent gbit anyway).

btw, not sure what the uk does, but here in the us the term 'ring' wire refers to the plug the operators and telco used; it has nothing to do with the ringer. Tip & Ring faq

A little off topic, check out Sparkfun's portable rotary telephone project. They also have a ringer cicruit posted.

[edit]

Looking back at your original post, I'm surprised by no mention of the black wire - I think if you inspect the cable more thoroughly you might find there's a black wire in there...


Yup this all sounds right and I agree. I was thinking much of the same stuff reading the thread and then what I was going to say had been posted. I will go with a big ditto on this advice. Pop that old phone open pull out the wires, clean the connections and solder new wire in I bet it's just a little corrosion on a connector or a wire thats got condensation under the jacket.
Your making me miss my old puke green rotery phone I used to call friends with when I was in junior high.
 
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Not sure if this is right but from what I remember, there used to be black and yellow wires in one phone we had when I was younger. It used to light up and it got its power from a transformer block which feed the power into all the phone jacks in the house via the black and yellow wires. Maybe the phone needs more power [from the yellow wire] to ring? The only thing is, where is the black wire?
 

agent420

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Actually, I saw a reference to using the Yel/Blk for low-voltage lighting in the last link I posted, but all the illuminated phones I remember as a kid drew their power from the standard RG pair.

That style mechanical ringer was always powered by the standard RG pair (which is why you don't want to be touching them when there is an incoming call :eek: )
 

webbee

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I have two trimline phones in my house that have the mechanical bell circuts active, both ring with xmas colors used as hook-up. We also have some electronic phones on the same circut. I agree with the other posters that it is in your phone. I suppose you could add more modern componets. Have you tried looking at thrift stores for any bell ringing phones to use for parts? Good luck with your project.
 

weasel2htm

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loquacious1285 said:
Not sure if this is right but from what I remember, there used to be black and yellow wires in one phone we had when I was younger. It used to light up and it got its power from a transformer block which feed the power into all the phone jacks in the house via the black and yellow wires. Maybe the phone needs more power [from the yellow wire] to ring? The only thing is, where is the black wire?
We still have the x-fmr block hooked up at my house, phones are long gone though.
BTW the ring frequency is 30Hz
 
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I know this post is ancient but it seems like a lot information on this thread regarding the yellow wire on the telephone (not from the wall) is wrong. When the wiring is coming from the telephone (not from the wall), the red and green wires are the ones for connecting to the phone line. The yellow wire was used to control the ringer; if you wanted the phone to ring, you'd connect the yellow wire to the green terminal on a jack like the 42A. If you didn't want it to wring, you'd connect it to the yellow terminal on the 42A. If there was a fourth black wire, it normally wasn't used on a single line phone. People are correct on this thread commenting that black and yellow terminals were used for a second phone line but that is irrelevant to the OP question. Modern phone lines have enough power to ring these phones still - but the number has always been limited to about 3 phones.

Another poster commented about using yellow/black for low-voltage lighting - I'm not sure about that. The Princess Telephone had 5 wires: red green, yellow, black, white. The red and green connected to the phone line. The yellow wire was the ringer wire (connect to green for ringing). The black and white wires were ultimately connected to a transformer 110V to 12VDC that powered the dial light.
 
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