DC Voltage Recorder Question

I'd like to record the voltage coming into my home/office telephone system.
I'm having an intermittent problem, where I get either no service or rapid clicking. This has been going on for about 3 or 4 months, mostly in the middle of the night. I've been able to catch it twice at the interface box, and found no dial tone or voltage.
I've had Verizon here 3 times (daytime), and they tell me they can't find any problem with their service, so the problem must be in my phone system. The last time they came out, I already had the house wiring disconnected at the interface, and their technician still insisted the problem must be in the house, because he had good voltage coming into the box. They even billed me $96 to come out.
I do HVAC work, and with the recent cold snap, people are trying to call, but not getting through.
I'm looking for a DC voltage recorder. I'm not trying to be cheap, but I'll probably only use it one time, so I'd prefer that it were as inexpensive as possible. Does anyone know of a DC voltage recorder that I could use? TIA Bob
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Look for a MultiMeter (DMM) with a PC interface and software. That way, you have a useful tool when you are finished with this need. I think Protek makes a reasonably priced one and Tektronics makes a suitable one also but the S/W and interface cable are extra.
Sounds like you have an intermittant open and you are trying to see if there is any pattern to when it happens (like when the rats are hungry).
Buy the inside line service contract for your phone service, it is usually a few bucks a month, then make the service call.
Wire a phone jack directly to the first point the wire enters your building (usually on the outside of the building) and run a long cord inside. If it is intermittant on this line it is verizon's responsibility. If it goes out on your regular phone but not this directly wired one, it is in your building. The point of entry is the property line WRT the wire.
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I Just reread more carefilly
An intermittant short inside the house would clamp the voltage to 0V and kill the dialtone. This would be undetectable with the house wiring disconnected. You can connect a regular battery across your phone line and monitor the voltage drop while moving about the house.
Look for a battery powered corded phone with a low battery, or a cheap electronic phone.
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He likely already has that, built inside the Network Interface Device ("the box").
I had a problem with SBC service at home several summers ago where the line was going totally dead (no tone...no voltage) and they kept saying it was my DSL service and the DSL people (Earthlink but physically it's Covad) said no way can anything we do knock out dialtone. I don't know the details of what the DSL people put at the C.O. (some sort of combiner thing) or whether that can in fact fail in a way that takes out POTS but eventually it was cured. But not before the SBC techs started getting annoyed that I kept calling for service. But what was I supposed to do? The phone line was dead...dead at the NID...so to me that means call the phoneco and tell them to fix it. Then the line would work again and I'd assumed it was because they'd fixed it in response to my calling but then later a tech would come out and of course by then it was working.
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On Thu, 15 Dec 2005 22:55:46 GMT, Steve Kraus

istm iirc that if one shorts the red and the green for a little while, it's possible to "blow a fuse" at the central office. I mean, I don't know if I blew a fuse or something else, but the line would be almost dead. No dial tone, just a little faint noise.
I would wait maybe 10 minutes and it would be good again.
How this might fit in to any of your problems, I can't say.
IIRC, I did this first with pay phones, but don't tell anyone.
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Just a thought, does this line have any kind of remote meter reading associated with it? This could possibly be opening the line depending on how it is implemented.
mm wrote:

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No, you don't blow a fuse. The CO switch detects excess current flowing and takes the line out of service. It checks it every few seconds, and when it finds that you are back to normal (i.e. open) the switch restores you to normal service. All automagic.
--
Rich Greenberg Marietta, GA, USA richgr atsign panix.com + 1 770 321 6507
Eastern time. N6LRT I speak for myself & my dogs only. VM\'er since CP-67
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Rich Greenberg wrote:

the ole false cross and grounds "perm". when a phone is left off hook, you will typically get dial tone, then a recording "to make a call", then the "howler", then the telephone office will pull the line from the equipment PERManently until the phone gets put back on hook. All these steps are based on a ~25 second "office" clock. dial tone lasts 25 sec, the howler last 25 sec, the perm is checked every 25 sec to see if the phone was put back on hook. If it was, the line is put back on the equipment.
A phone isn't the only thing that can look like a phone off-hook, shorted phones, wet cable, or either wire shorted to ground.
to the op, check the alarm system! also, most phone offices do an autotest during the night time (some during the day too). there is no real schedule to this testing, but is based more on when the equipment gets done with all the other lines and gets back to your line again. this test usually lasts about 10 seconds, your line (two wires) is disconnected from the regular equipment, then tested for leakage to each other and to ground and then tested with about 100v DC for breakdown. This lets them find lines that are developing problems and fix cable faults before they take down a neighborhood. If the line is in use, or you pick up the phone, the test is dumped immediately and line returned to the equipment, you'll never know the test was happening. Some line status lamps (old att centrex line displays) will blink on a few times while this test is in progress. I used to watch our four lines do this dance all night long ;-)
also remember, your open circuit could just as well be a short (both will be 0 volts). Watch your line voltage when you're on the phone and the "clicking" occurs. An analog meter works best, is the reading bouncing all over the place? And does it continue if you hang up the phone immediately? That's a sign of wet cable between you and the office. Is your protector (network interface) carbon blocks or gas tubes? carbons are notorious for noise and shorts.
Intermittants are are always a pain, good luck.
-larry / dallas
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Can that test take place if there is DSL without disrupting it?
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Steve Kraus wrote:

yes and no
yes, if your dsl equipped line is metallic (pair of copper wires) the whole way from your house to the telephone office. the dsl signal is inserted at the phone office between the regular line equipment (where the test happens) and the "frame" where your line leaves the office. the dsl insertion is just sets of coils in series with your pair of wires and "looks" like a few "extra" feet of wire that is ignored in the test. it helps if you think of dsl as just a radio signal that rides along your copper wire. the phone service is dc and ac up to about 4 kHz (audio), and the dsl service is anything higher, limited to length and how crappy the wire is to radio waves. neither service knows the other is there, unless you forget the filters on the phones. Phones look like short circuits to radio waves -by design -especially for folks with phone lines near a radio or tv transmitter ;-)
no, if your dsl equipped phone service is feed from a hut or rt (aka dslam, remote terminal, pair gain, pedestal) in your neighborhood. The hut usually has fiber optic connections back to the main phone office. In the hut, phone service starts from a "channel bank", that can't do tests, followed by the dsl insertion, then on to your house. The phone company can still test your line, but there might only be one "tester" in each hut, which can disconnect one line from the hut at a time to run the line test. All the ones I've seen are used as needed from a test center by a tech to work a repair order. Your line is out of service (dsl too) while the tech runs tests on your line.
Some companies might have automated testing in huts, but it wouldn't be user friendly like the main office test. btw - office based automated line testing can be programmed off. But it's best left on since it is transparent to the user, and does speed up service restores on cable cuts. It alarms pretty fast when it gets a bunch of "opens" on a cable in a short period of time.
here, the borg has put huts everywhere, and almost all new dsl is from huts, some legacy dsl is still copper to the office. and overground tel(until the trencher gets by in a few months to dig in the cable) is now doing fios, fiber optic cable to the customer backdoor.
-larry / dallas
if you want the long version of how dsl works, google "adsl carrier frequency"
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Steve Kraus wrote:

i missed the target -
in the case of copper all the way, the dsl connection would remain up during the test, just like it does while you're on the phone and even while ringing. And ringing is a nasty 90 (125 v peak) volts ac rms at 20 Hz superimposed on -50 volts dc. There might be some errors introduced, which would be resent data. I've never seen my dsl modem retrain on ringing. You can look at the dsl modem diagnostics and see how many send and receive errors are counted.
I just did a test on my line: ringing, and pulse dialing caused no errors.
i'm running at: Noise Margin:     22.0 dB (Downstream), 22.0 db (Upstream) Attenuation:     11.0 dB (Downstream), 7.0 db (Upstream)
Data Errors Statistics Collected for 4:17:03 ATM Cell Header Errors:0     ATM Loss of Cell Delineation:0 DSL Link Retrains:0 DSL Training Errors:0 DSL Training Timeouts:0 DSL Loss of Framing Failures:0 DSL Loss of Signal Failures:0 DSL Loss of Power Failures:0 DSL Loss of Margin Failures:0 DSL Cumulative Errored Seconds:0 DSL Severely Errored Seconds:0 DSL Corrected Blocks:0 DSL Uncorrected Blocks:0 ISP Connection Establishment:1
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Bob wrote:

As PipeDown said, a digital meter with RS322 port will do it inexpensively. They come with Windows logging software that will plot the results for you. I've used these in the past with great results.
There are a few examples on eBay: http://search.ebay.com/ws/search/AdvSearch?sofindtype 
Item # 7523541926 7571189952     7571767028    
Jim
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These meters look great, I wish I could think of a good reason to buy one.
I do have a meter with a temperature probe. At the end it has 1mm of metal showing, a one inch piece of blue heatshrink tubing, and the wire is insulated with some woven almost smooth, almost shiny white stuff with a blue line spiraling down the wire.
Do you think this probe is waterproof?
I wanted to use it but wasn't sure and ended up using a meat thermometer in the 190 degree water. That worked this time, but the meter has a much broader range and if I could use it in liquids, that would be great.
The manual says nothing about liquids or not.

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mm wrote:

I should think you could use it. The probes in the meters listed are thermocouple type and even if water seeped into the probe sheath the reading wouldn't be greatly affected. Jim

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Thanks. I"ll try it. come to think, if it's not hot liquid, it would have to be fire! I don't think I have anything else that would be hotter than say, 120 degrees.
You wouldn't use it in fire, would you? I hadn't even thought of that before.

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Thanks to everyone for your help. When this first started, I unplugged the jack from the house/office lines at the interface and ran a phone wire out my window to the interface. I was quick enough to catch it 2 times, so I'm almost positive the problem is incoming voltage. That's not to say there couldn't be another problem, but I've checked every inch of inside wiring, and every connection, and disconnected some phones. It's just my wife and me, and this happens mostly in the middle of the night. I don't have a problem with $200 or $300 if I knew I'd use it again, but in 25 years of HVAC service, I've never needed one before. I already have a UEI DL250, which does everything I need, so I'll probably get the Mastech MAS-345 on eBay for $41. Thanks Jim. I'm not too familiar with DC voltage. Can I connect the test leads in parallel with the phone lines, while they are still connected, or do I have to disconnect the phones completely while the recording is being done? TIA Bob
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Bob wrote:<SNIP>

Extend the test leads to the terminals at the outside "jack" or interface box. But, also disconnect the wires which feed into the house from the terminal. That way *only* distrurbances on the utility side will affect the readings.
Jim
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I guess since this only happens during the middle of the night, this won't inconvenience him, but during the day, I think he could plug in one telephone. If he logs the time he plugs and unplugs, it will even show that his telephone doesn't cause a voltage change.
In fact, he could plug in his whole system during the day and if that does't cause a voltage change, that would let it off the hook, except only for causing voltage changes. I lost track. Do we know yet that the phone company will accept that it is the voltage change/spike that causes the problem?

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Bob,
Are you sure that you don't have an alarm panel tied into your phone line? Typically, there should be a series jack installed that has dialtone from the NID coming into it on a pair of wires (Red / Green or possibly White / Blue) on terminals 4 & 5 and another pair (Yellow / Black or White / Orange) on terminals 1 & 8 going back out to the "house" wiring. There are a pair of shorting bars inside the jack that connect both pairs together when there is no plug inserted into it, thus allowing your phones to work. When the plug from an alarm panel is plugged into the jack, the shorting bars are lifted and dialtone now goes through the panel's internal dialer, which, when tripped, will turn off the "house" side of the jack, thereby keeping the phone line free to dial out to a central monitoring station, so that either burglar or fire codes may be sent and the appropriate responders notified. If the dialer is trying to call out, it will most definitely shut off dialtone to the house. The clicking that you hear could possibly just be bleed over from the adjacent pair of wires depending upon the quality or lack thereof of the wire being used.
If you do have one of these installed, you may have to have your local Telco check out the jack or your alarm company check out the panel. Keep in mind that if you unplug the alarm panel from the jack you WILL NOT be protected. Be sure to PLUG IT BACK IN for security reasons.
Most people take their alarm panels for granted and often forget that they are tied into their phone line.
Hope this helps. Let us know how you make out.
Peter.

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