Telephone voltage

[Slowpoke]

I had no dial tone last week and called AT&T. They said the problem was mine. About an hour later, before I did any thing, the dial tone was back.
Now it's gone again. I took a working phone and connected it to the customer check receptical in the demarcation box (which was installed for a second line, no longer in service) on the outside wall of the house. No dial tone there. There are two wires coming from the pole to the small original 4 wire box installed in the 60s, the one with a rubber cover.... there is only 1.5 dc volts there. Should there be a constant 48 volts? If there is "no" voltage there, can AT&T say it's my problem when I call? I suspsect the squirels have something to do with it.
THanks.

 

[tech4]

It should be 48 volts with no phone off the hook. Disconnect one wire on the house side and see if the voltage goes up - if it does you have a problem in the house. I had that and it was the modem in my computer had shorted. If you call AT&T and the problem is in the house, you will be charged.

 

[buickanddeere]

48V talk or on the hook. 96V to ring.
I was doing fine live splicing a temporary phone line the neighbor cut with a mower.Just my luck somebody rang, 96V DC has a bite.

 

[Slowpoke]

OK, I"ll try that. But if there is a dead short caused by a modem or something else, why doesn"t it cause problems for phones in other houses? Is there an auto reset breaker for my line on the pole that senses the short?

 

[tomga]

disconnect or unplug all your inside wiring outside. if you have more than 1 line coming in make sure you are testing the right line. you will have 48v straight across a good line. a short toward the co will shunt the voltage down lower. going to ground with your meter you will have 48v on the ring side of the line and a ground on the tip side. the ground resistance will vary according to the distance to co or carrier system.

 

[willie in mn]

Slowpoke
In a nutshell, hope this helps. The vacant second line, the one no longer in service, would be "clear capped" at your terninal, so read nothing. This would be done at the pedastal if underground or on the pole if overhead.
Need to be testing the original connector if that is the one your working line is using. A little fiddle work, but not difficult. If there are fuses in the rubber covered connector, pull them or disconnect your house wire & recheck the incoming line, should read 48 volt "talk battery" if line is ok that far, & the trouble is in the house.
If incoming line is ok, re-connect wires & unplug everything in the house that is in service, including phones, answering machine & computers, re-test.
If this clears trouble, you have a bad instrument, plug in one at a time until you find the one that shorts it out. If it doesn't clear, you have bad internal wire.
About the short not causing trouble in other houses- the days of party lines are pretty much gone. Each line is a seperate "cable pair" going back to the central exchange, as many as 4000 pair in a cable.
A shorted pair won't trip a breaker. The old "pulse dial", or rotary dial system worked by make-break a short to trigger the switch gear. EG: quickly make-break 3 times to dial a 3, 4 times to dial a 4 etc., then a quick pause, dial the next number.
Now I have you thoroughly confused.
Willie- ex military cable tech.

 

[Anonymous-0]

We had a lighting strike about 10 feet from the house and it knocked out one of our 5 phones. the line went dead until we disconnected that bad phone. It cost $60 for the phone company repairman to come out and find the problem. Try disconnecting the line and or phones before calling the phone repairman.

 

[ArkanDan]

In the "old days" that ring voltage would have been AC. Not so sure it still isn't, but times they are a changing so who knows.?

 

[tech4]

You have a direct line and a short will not affect any other line in the neighborhood. The phone line will be low 5-6 volts or lower when a phone is off hook. It is 48v only when all phones are on hook. If the line from the pole is disconnected from the house and it has 48 volts then the problem is in the house.

 

[tech4]

The ringer voltage is 20Hz 90 volts. It is AC because the ringer is isolated with a capacitor in the old phones.

 

[ArkanDan]

That would be the "straight line" ring voltage, right? There used to be 30, 42, 54, and 66 cycle/hertz too. Nostalgia land.

 

[IH2444]

Yep you are correct and there is/was also bridged and grounded ringing.

And cadence ringing for party lines ie one long and one short ring or 2 longs, etc.

 

[Slowpoke]

The cable with two wires from the pole has 1.5 volts dc between them. There is a stud in the box with a couple of wires attached which may be grounded to a water pipe under the house, but I can't tell without going under and looking. Do I test the voltage from the each wire in the cable to what may be ground to get the 48 volts or just across the 2 wires?

 

[tech4]

If you only have 1.5 volts on the pair from the pole with the house disconnected - then the problem is with AT&T. The wire to the stud is ground. One of the wires from AT&T is ground but it is grounded back at the CO. If your phone line was grounded - you will hear a real loud 60 cycle hum. The phone company has a positive ground. Be sure the line from the pole is open to the box because some of the old demarcs have carbon blocks that short to ground with over voltage or lightning strikes.

 

[Mark - IN.]

Its entirely possible that you could measure -48 VDC talk battery when off hook, but not ring in because of a cracked or broken wire that won't support loop current on incoming ring, which is AC, but can be anwhere from like 60 VAC to 90 VAC depending on what kind of equipment that it is coming out of. Direct feed all the way back to a central office? Might go back to a vault if its fairly new construction.

At the back of your house you may have a network interface that opens up on the "customer side" and allows you to unplug a modular plug and plug a phone in. If you have dialtone at that point going back towards the central office equipment, and you can call that phone and it rings (don't use a cordless), chances are the line is good, but not necessarily. It could be that a spliced pair somewhere is wet and shorting, but after the frost or whatever clears and dries, the line is good. Next morning, same problem, wet pair, pair dries, line clears. So...try it periodically throughout the day and see what happens. If its always clear at that modular plug in but not good inside the house, well, chances are good its in the house. 90% of all failures are caused by cordless phones going or being bad. Unplug all of your phones, Caller ID boxes, AND computer modems that may be shorting out (answering as far as telco equipment is concerned), and use an old Bell phone or some plain jane phone that aint cordless and plug it in and see what happens.

Bottom line...if its good at the customer side of the network interface going back towards the source, the problem is probably yours inside your house. If its bad at any time or point going back towards the source, then its telco's problem. The problem with testers these days, many never test beyond the telco equipment out to the house and see a piece of equipment (phone plugged in). Some pieces of equipment will not test beyond a card in a CV vault anyway, so the cable pair never gets tested, and neither does a physical telephone.

Good Luck.

Mark

 

[bc]

With buried lines, sometimes the clay in the ground during its frost/heave cycles will pull the wire loose from the box either at the house or the closest box where it ties into the main line. Suppose it could also affect a bad spot in the wire. Of course it could happen anywhere on AT&T lines. Helps to keep any places where wire comes out of the ground to keep it damp so the ground doesn't dry out. Also freezing weather and ice causes wires to contract and bind up, particularly with overhead lines.

I bought a cheap tone generator setup at HF for tracing lines. Haven't used it yet.

At&t will always blame it on the subscriber. They have a diagnostic test procedure they can run when you call them. I've lost servive before, call them to hear it is on my side, but somehow within an hour of my call, service is restored. Go figure. I lose the dsl every so often as well. I used to jack with the router settings for an hour or so every time it happened, I have finally learned to wait it out and sure enough service is back after while. I know it is at&t doing this.

 

[Slowpoke]

Lines are overhead, no ice. I called one of the AT&T repair numbers on the 22nd and never talked to a human , on hold for 30 minutes.
Called the same number on the 23rd, no human after 1 1/2 hours on hold. On the 24th, I called a different number and in 10 minutes got the computer to send a tech. He is so busy that he can't show up till Dec. 30, and it could be anytime between 8am & 8pm.
So I'm using a computer wherever I can find one: friend, library, etc.


GOT AT&T?

 

[Slowpoke]

Incoming 2 wire cable from the pole was disconnected at the 1962 "interface" (small terminal with rubber cover) and there is 1.5 volts dc between the 2 wires.

 

[john *.?-!.* cub owner]

(quoted from post at 22:32:09 12/25/10) Incoming 2 wire cable from the pole was disconnected at the 1962 "interface" (small terminal with rubber cover) and there is 1.5 volts dc between the 2 wires.

ssuming that 1.5 volts was on the wire coming down the pole with your house disconnected, the problem is on the phone company side, most likely a partial short.

Regarding your problems getting calls to the phone company answered, and the long repair times, I suggest you file a com0plaint with your local PSC in your state. I am retired from Centurytel, and that long a delay time is not acceptable. Our management would be looking to hang someone over it, as well as the state PSC commission being all over them.

 

[Slowpoke]

Well, Cub owner John, the phone magically returned to service sometime Sunday and I'm back on the air. Now I wonder if I should cancel the repair order or spend 12 hours waiting for the tech on Thursday. Or maybe the line will go off by Thursday.

A friend several miles away also lost his service and blames it on the rain we've had for the last two weeks.