Help me get my dial tone back!

April 20, 2008 6:50 AM

Weird phone behavior filter: I can't get a dial tone for hours. How to fix this?

It often happens that whenever someone calls us, after the call is over we can't get a dial tone. Sometimes we are without a dial tone for hours. We want to stop this.

I have no idea which of any of these are relevant facts:

I have an AT&T answering machine with three cordless phones attached to it on the home line. We have call waiting. Sometimes, after we receive calls and they end, we can't get a dial tone. I pick up all three phones and turn them off, and I also make sure the speaker phone is turned off. When I turn them on and listen, I get a dead silence. When I use another line (eg, my cell phone) to call my home phone, I get a busy signal (which presumably shouldn't happen with call waiting anyway), so perhaps this means that my phone setup thinks that a call is in process somewhere. After a couple of hours, this process resolves itself.

Perhaps the most relevant fact is the special behavior of the "in use" light on my answering machine. Usually the light is off; when I make or receive a call, it's on. During the weird and unsavory behavior when the phone line is unusable, the light BLINKS ON AND OFF. Barring demonic possession, what is your theory, diagnosis, and recommended cure for this problem?

posted by Mr. Justice to technology (11 comments total)

It's likely that your answering machine, one of your phones, or some other kind of phone device like a caller ID unit is acting like it is off the hook, even though it appears to be hung up or off. You need to unplug them one at a time from the phone jack(s) and see if that solves the problem.
posted by 14580 at 7:21 AM on April 20

Have you tried disconnecting the answering machine when it is blinking? You need to eliminate that possibility before checking other things.
posted by Forktine at 7:22 AM on April 20

Isolate the problem. Remove one device from the setup, do some tests, see if it happens again. If it does, remove the next device from the setup, repeat.

If it continues, call your local phone service provider and see if they have any suggestions or can perform any tests.

This is a big deal. If something were to happen and you can't get a line out to emergency services, you're in some trouble.
posted by phredgreen at 7:24 AM on April 20

BTW, if you leave a phone off the hook long enough the phone switch will take it out of service, and your phone service won't restore until the phone is hung-up. During that time you don't have phone service and your caller ID is not going to work.

Also, a short in your phone wiring will also work like a phone that is off the hook.
posted by 14580 at 7:25 AM on April 20 [1 favorite]

I would suggest disconnecting all your equipment except for one phone (your simplest one) and see if the problem continues. This will tell you if any of your equipment is not behaving properly. If it continues though then you should call the telco repair service ASAP, since it's something that can prevent you from making emergency calls.

On the other hand, I'm aware that the phone system has some weird behavior where it allows a call to remain connected even if only one party hangs up... I wonder if the other person you're talking to is not hanging up the line properly? Maybe someone more knowledgeable about telephone equipment can provide more info about what circumstances would allow a call to remain connected like this... I've never figured it out.
posted by mr. creosote at 7:27 AM on April 20

This may be totally useless, but back in the 80's, I had a friend who had the same issue in an apartment. What turned out to be the problem was a unit that the telco had installed on the line to boost the current for dialtone and ring voltage on an old line that had otherwise insufficient voltage.

This unit contained a battery and some sort of trickle-charging mechanism, and over time, the battery had degraded to the point where after ringing the phones, it took hours for it to charge up enough to provide dialtone, another ring voltage, etc. It took the telco guy about two minutes to diagnose the problem and replace the unit.

I have no idea if units like this were ever in widespread use, or if they were, whether there are any of them (or any similar devices) still in service today.

I agree with mr. creosote on the approach for trouble-shooting this -- unhook everything except the simplest phone you have or can borrow, and see if you can duplicate the problem. If you can, call the telco and insist they send someone out, despite the usual dire warnings that they'll charge you a fortune if it's your problem. If you can' duplicate the problem in this way, then plug the equipment back in one unit at a time until you find the defective part, and either have it repaired or replace it.
posted by nonliteral at 8:31 AM on April 20

No dial tone from inside and busy signal from the outside could be a dead short or the line has lost the ground. But yeah, the first thing to do is disco everything and start checking with one single line phone. If the phone company comes out, the first thing they will do is blame whatever's plugged into the system, so you want to get everything off before you call them (if you do). They only have to give you a dial tone to the network interface, which is the new name for the demarc. That's the box in the back of the house where the service comes in from the outside world. Usually, there's a way you can can plug your phone into that and check it there. If it's screwed up inside the house, you have to pay them to fix it, unless you have some kind of insurance with them.
The old demarc usually had two doors, a big one that doesn't really go anywhere interesting, and slightly smaller inside one that requires a special tool to open. Normally, a quarter will fit in the slot. Sometimes there's a very short cord that fits into the outside world connection and you can unplug that and put the phone into it, which will tell you if it's inside or outside.
The timing is sort of confusing. Usually it's either dead or it's not, and if it's intermittent, it's usually weather, wind or rain. So all of this could be completely irrelevant. I have to talk people through this on the phone once in a while, and that's where we start. Because of the timing, I'd just unplug all the stuff, and put one piece at a time back on the line, and I'll bet you find it.
posted by unrepentanthippie at 9:10 AM on April 20

Should have previewed, slow typist.
Yeah, what he said.
posted by unrepentanthippie at 9:12 AM on April 20

Also, do you by any chance have an alarm system installed? They often connect to the telephone lines to communicate with the monitoring station, and it may cut off normal telephone use while this is going on (to keep a thief from shutting down the alarm by taking a phone off the hook). Most alarms will disable call waiting as well. Given the behavior of your answering machine, I'm highly inclined to think that the machine is the culprit, but it's worth checking your alarm if you have one.
posted by zachlipton at 2:53 PM on April 20

This is really embarrassing. It is also the answer to the question.

I called the phone company to report the problem. The response: "Yes, we've been working on a cable in your area. The problem should end by day after tomorrow." And it did.

I apologize for wasting everyone's time.
posted by Mr. Justice at 8:20 AM on April 27

No need to be embarrassed or apologize whatsoever.
It was a very weird problem, and all the answers were great, and some day, somebody will go looking for the answer to something similar, find this thread, and will figure out their problem without even having to post a question.
You were looking for a local problem, as were we all, and nobody would have suspected that the telco themselves created the problem. (We all sort of assume that the signal they provide to the demarc is reasonably clean.)
posted by unrepentanthippie at 11:45 AM on May 17