enter image description hereThis is the old connection block as the wires come into our cottage.

We have been trying to figure out why the phone stopped working old telephone junction box

inside box

outside the box

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    So this is nothing but an old-style telephone connection block. The telephone utility service is coming in at the bottom, the two cylindrical brown things are fuses, and your phone(s) hook up at the top. Apart from the corrosion, dust, fuzz, and ancient wires what's the problem?
    – jwh20
    Commented Aug 3, 2022 at 0:43
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    Story time: My father and I went to visit his sister. I hadn't been to her house in probably 20 years at that point. The idea was to install a modem and connect it to her PC for email (yeah, this happened a good while back.) I hooked up the modem to the phone line she had had installed years earlier for fax. The modem wouldn't work. My aunt then mentioned that the fax had never worked right, either. I found the modem wasn't getting a dial tone - the line was dead. I traced the wiring through the house and out to the connection on the ouside wall. Everything looked OK.
    – JRE
    Commented Aug 3, 2022 at 13:02
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    While looking at the outside junction box, I pulled on the wires going to the house - and one of them pulled out of the insulation. The wire had been broken about an inch up inside the insulation. Some of the time the broken ends would make contact and the fax would work. Sometimes they lost contact and the fax quit working. My aunt said had been that way since it was installed some 25 years before. The phone company had been out several times but never found the problem. I fixed the broken wire. The modem worked perfectly after that.
    – JRE
    Commented Aug 3, 2022 at 13:05
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    @SeanB Please be clear what what you mean by "not working" then. When you call it from the outside does it ring? Generally you test by connecting to the input terminals after disconnecting them from the line in the house. If that works then your problem is the inside wiring. If not, then the problem is the outside wiring which is the TELCO's responsibility.
    – jwh20
    Commented Aug 3, 2022 at 14:20
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    You "can call it from outside" - does the cottage phone ring, and you pick it up, and talk to the person calling? Or you just "hear ringing" on the phone calling it, which means exactly nothing about the connection to your cottage? It would be very odd to have a call connect from outside and not have dialtone. Please provide a picture of your outside box, and if it has a spot that says "customer access" (or something like that) unscrew the screw there and provide a picture with it open. There should be a spot there you can plug right into to test.
    – Ecnerwal
    Commented Aug 3, 2022 at 22:12

4 Answers 4


The way to test this is with a telephone test set:

Fluke test set

The gold standard is a major manufacturer such as the Fluke pictured above. But in reality, all you really need is a cheap phone with something that splits the modular wiring into alligator clips, like this cheapie from Amazon:

cheap test set

You then work your way through the wiring, starting with the two sides of this block, until you find where it does and doesn't work. Then you troubleshoot the problem, unless you have no signal even where the wires first come into the building - in which case it is a telco problem.

Based on the new pictures, there is a modern network interface on the outside wall. If you get a dial tone there then it is an internal wiring problem. If you don't then it is a telco problem. Troubleshoot from that outside box step by step all the way to your regular phone jack inside. Somewhere along the way, you will find a bad connection or (less likely) a broken wire.

P.S. Make sure somebody paid the phone bill.

  • On newer installs, there's usually a pair of RJ-11 jacks in that interface box that are jumpered together. With that kind of interface, you can just unplug the cable from the jack coming off the wires from the pole and plug in a standard handset. The installation in that photo looks like it predates RJ-11s.
    – SteveSh
    Commented Aug 3, 2022 at 1:25
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    +1 for the phone bill. Always ask this first. I knew someone who threw away a "broken" tv and replaced it: the Cable service wasn't paid up.
    – Yorik
    Commented Aug 3, 2022 at 19:45
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    Another tester is simply a known-good telephone (don't assume a new one is good; plug it into a working phone jack somewhere) plus a known-good cord. Plug it into the test jack in the network interface. Commented Aug 5, 2022 at 17:19

Are you quite sure this is actively in play, or is it just left-over?

It's a very stock, very old telephone interface.

In most places where those were used, the telephone company moved the actual interface (decades ago now) to a bland gray or tan box on the outside of the building with a normal screw you can unscrew to access your part of it, and a special screw for the telephone company access. That became the interface, and the item in your picture became a thing left behind, as they didn't have any use for it, and the whole point of pushing the interface point outside was so they didn't have responsibility for wires inside your house. So, I'd double check that there isn't one of those outside where the wire comes in. If there is, you can open your part of it and plug in a telephone with a modern jack, which allows you to test if their line works to that point.

If it does, the wiring in your house/cottage is at fault. If it does not, they need to fix the line coming to your house.

In the (IMHO, wildly) unlikely event that this thing is still their interface, if you connect the red and green wires of a standard jack to the two black wires on the bottom in your picture, that will bypass the bits of this thing that could fail and connect you directly to their line, and you can plug in a phone to test it that way. Red to the left, green to the right, as you can see above. If that does not work, and this is really their interface, it's their problem to fix. If you then connect the red and green of your jack to the upper set of blue-corroded terminals and it does not work, this thing is broken, and it's still their problem. A correct test would disconnect (but keep track of) all the wires connected to the top terminals, in case one of those pairs is shorted, causing the problem. Then reconnect one at a time and verify operation (or failure) and disconnect any that cause failure for further troubleshooting.

In the likely event that this is no longer the active interface, removal would be a reasonable part of cleaning up the in-house wiring.

  • thank you for the detail. The Telco has a gray box on the outside of the cottage where the line from the pole comes to. From that gray box a wire comes into the house and connects to this artifact :-) I will give a try at connecting to the bottom wires and see if I can get a tone.
    – Sean B
    Commented Aug 3, 2022 at 13:39
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    Give us a picture of the gray box. There may be a simpler way to check the line.
    – Ecnerwal
    Commented Aug 3, 2022 at 16:42
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    @SeanB so, as expected, the actual line interface (now) is that gray box. Unclip the gray parts that say "contains half-ringer" to reveal a place to plug in a normal RJ11 modular phone cord. They've wired for two possible lines, likely only one is active, the one on the right. If it doesn't work, try the one on the left. THAT is where you test, and you don't need to unscrew anything but the cover you already unscrewed. If the line works there, you'll just need to repair (or replace, good plan given what you have) wiring going into the cottage.
    – Ecnerwal
    Commented Aug 4, 2022 at 16:53
  • a thank you the one on the right has time. The purple with white and white with purple coming out of it connect to the old wire coming into the cottage and connecting to the bottom of the unit in the first picture. So is it correct that I can cut and splice to the purple and white wires and run new wire into the house straight to the phone jack?
    – Sean B
    Commented Aug 4, 2022 at 21:48
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    All of you are fantastic. Thank you for walking me through this. I got it to work.
    – Sean B
    Commented Aug 5, 2022 at 16:37

This is the WWII telco lightning protection junction box with fuses, insulation and carbon current limiters with a cap over the arc zone. It is the interface to inside premises also called the "demarcation zone" for user-purchased phone equipment.


The demarcation point varies from building type and service level. In its simplest form, the demarcation point is a junction block where telephone extensions join to connect to the network. This junction block usually includes a lightning arrester (which requires a wire to ground). In multi-line installations such as businesses or apartment buildings, the demarcation point may be a punch down block. In most places this hardware existed before deregulation.


These are little doors designed for testing. They are hinged at the bottom and clipped at the top. When you open them, your house interior wiring becomes disconnected from the phone company wiring, and they expose a phone jack into which you can plug in any phone with an RJ11 plug. Presumably you have one.

The easiest and first test is to do that. Open the door, plug a phone, one known to work, into the jack. If the phone works, you know the problem is inside your house. If it doesn't work, it's not your problem .. you report it to the phone company.

Then, if the problem is inside your house, you can follow the advice in the other answers. But my solution is to rip out ALL the interior phone wiring, and plug a portable phone base station into a jack that is connected DIRECTLY to the wiring coming out of the gray exterior box. Completely eliminate all historical inside phone wiring. Buy a system with as many portable phones as you need.

Eventually you will replace this gray box and the copper phone service with VOIP. When that happens you just move the base station to the router, instead of having to connect the router to your house phone wiring, which would be ridiculously ironic if you kept this 1930s lightning gizmo in the circuit!

enter image description here

  • 1
    @Ecnerwal of course. Corrected. Last time I crimped an RJ11 was 2012. August 2012 in fact when I moved into this house. This is the 10 year anniversary of last time a crimped an RJ11. :)
    – jay613
    Commented Aug 4, 2022 at 17:03
  • yup tone in the right side connector. I will be running new wire. What color wire on the phone jack goes to the purple with white wire and which to the white with purple?
    – Sean B
    Commented Aug 4, 2022 at 21:54
  • In most phone jacks, the middle two pins are connected to red and green wires. If you buy a new jack and that's what you see, then the red wire in the jack should be connected to the red wire in the red/green pair in the grey box. USUALLY that will correspond to the wire that is mostly colored with white strips. But you ought to be able to visually confirm that. Red to purple with white stripes to red, green to white with purple stripes to green.
    – jay613
    Commented Aug 4, 2022 at 22:33
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    The terminals that the purple and white go into are color coded red and green, even...;^) You can't see that well (they are peeking out) since the test access door is closed in this picture. With it open, it's obvious. There are actually 4 sets (all going to the same pair) so you can run multiple extansions directly from here without any other splices, if you want.
    – Ecnerwal
    Commented Aug 4, 2022 at 23:40
  • BTW, purple/white is not a standard color pairing for phone wire. So, rely more on tracing them correctly to the same color (red or green) at each end, rather than on assuming any standard coding for them. But usually red ("Ring") corresponds to the solid color where there is solid paired with white.
    – jay613
    Commented Aug 5, 2022 at 13:00

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