Telephony?

[Blast it Tom!]

Ok, I know there are some good electronics/signals guys on here. I'm not one of them. I've tried "teh intarwebz" to no avail, even on the physics forums. This is an odd one, at least for me. I actually have a "land line" cordless phone with base station. It was plugged into a jack in the kitchen.

I have a combination internet/phone/cable deal (yeah, cable... sigh...) and so the phone eventually gets to the phone jack on my modem. The line from the modem, one from my combination printer/scanner/copier/fax (yes, fax! really!), and the jack from the kitchen met at a connection board in the garage right below my office. Last week the phone stopped working. So I brought the base station back here and plugged it directly into the modem. No problem. Keeee-rap, wiring? How do static connections go bad?

Today I spent all day (what I did today INSTEAD or rocketry...) on the dumb thing. I isolated the wire, checked continuity, even measured the diameter, estimated the length and calculated the resistance, which matched pretty well with the old formula - 2 ohms for 20 mil wire diameter and 80 ft round trip length - I shorted the ends together so I could check continuity and resistance from one end. That's in case anyone feels like checking me. Resistivity of copper at at 20°C... you know the drill.

Well, who knows, then? Continuity back to the pins in the jack seemed ok as well, so I cleaned all the connections and just twisted the ends together downstairs in case the board itself was what? Corroded? Sure didn't look any different than it ever had...

But though all components of this very uncomplicated system check out ok, I still get no dial tone when I plug the base into my kitchen jack. I can receive calls, but no dial tone.

The only possible external cause is that my provider (the only show in town) said they completed repairs and upgrades in my area. (They say it's in my wiring as well.) But could they, for instance, change some kind of threshold voltage for dial tone? Is my 40' of phone wire too far now? The fax still works fine, but the one purpose we needed it for went away last year, so for now I have the base unit back here, which cuts out the connection box downstairs and thus the paleolithic fax machine. But She Who Must Be Obeyed would very much like the base unit back in the kitchen. And I wanna run new wire about as much as I want a root canal sans novacaine.

So I appreciate any thoughts that all you electronics gurus out there might have. Much thanks for your charity.

 

[kuririn]

Try calling your service provider.
I think they would troubleshoot line problems for free.

 

[Tobor]

Okay, my knowledge of phone tech is OLD. But basically, there are two distinct voltages related to POTS (Plain Old Telephone Service) lines, Ring voltage and Talk voltage.
Talk voltage is 24V DC
Ring voltage is 110V AC

Okay think old Ma' Bell phones here. When the hand set is resting in it's cradle, it is "On Hook". When you pick up the handset, it is "Off Hook".
So, when a phone is On Hook, it can only respond to Ring voltage and when the phone is Off Hook, it only uses Talk voltage. Sound is transmitted by modulating Talk voltage. So Talk voltage is akin to a carrier wave, loosely speaking.

Testing:
Remove the cover on any phone jack. Using a multi-meter, set it to A/C and attach your probes to the screw terminals where the White/Blue - Blue wire pair attach. Using your cell phone, call your land line. You should see approx 110V AC pulsing across the terminals.

Repeat for DC, do NOT attach probes until after you have answered your land line. With probes attached, you should see approx 24V DC across the terminals.

Let me know what you find out.

Edit: If you only see solid colored wires in a jack, the Yellow and Green wires are your first pair (Or circuit) and the Red and Blue wires are your 2nd pair (or 2nd circuit). Each pair of wires represents a potential phone line. So by using two pairs of wires a single phone jack can service two phone lines.

 

[Blast it Tom!]

Try calling your service provider.
I think they would troubleshoot line problems for free.

Yeah, I did that, they said it's in my house wiring.

Okay, my knowledge of phone tech is OLD. But basically, there are two distinct voltages related to POTS (Plain Old Telephone Service) lines, Ring voltage and Talk voltage.
Talk voltage is 24V DC
Ring voltage is 110V AC

Okay think old Ma' Bell phones here. When the hand set is resting in it's cradle, it is "On Hook". When you pick up the handset, it is "Off Hook".
So, when a phone is On Hook, it can only respond to Ring voltage and when the phone is Off Hook, it only uses Talk voltage. Sound is transmitted by modulating Talk voltage. So Talk voltage is akin to a carrier wave, loosely speaking.

Testing:
Remove the cover on any phone jack. Using a multi-meter, set it to A/C and attach your probes to the screw terminals where the White/Blue - Blue wire pair attach. Using your cell phone, call your land line. You should see approx 110V AC pulsing across the terminals.

Repeat for DC, do NOT attach probes until after you have answered your land line. With probes attached, you should see approx 24V DC across the terminals.

Let me know what you find out.

Edit: If you only see solid colored wires in a jack, the Yellow and Green wires are your first pair (Or circuit) and the Red and Blue wires are your 2nd pair (or 2nd circuit). Each pair of wires represents a potential phone line. So by using two pairs of wires a single phone jack can service two phone lines.

Well, in this brave new world of internet telephony, all I have are red and green. But unless they are doing some digital signaling, your plan could yield some useful information. Thanks!

 

[neil_w]

Edit: If you only see solid colored wires in a jack, the Yellow and Green wires are your first pair (Or circuit) and the Red and Blue wires are your 2nd pair (or 2nd circuit). Each pair of wires represents a potential phone line. So by using two pairs of wires a single phone jack can service two phone lines.

?

First pair should be red/green, second pair is black/yellow, in every phone jack I've ever seen.

 

[Blast it Tom!]

Right, but my setup only uses the red-green pair. They have always been connected in parallel, that is, all reds together and all greens together. The inherent pair, to my understanding, is foe a second line. Maybe I need to be searching out VoIP info!

 

[neil_w]

Right, but my setup only uses the red-green pair. They have always been connected in parallel, that is, all reds together and all greens together.

That is correct for a one-line system.

 

[Marc_G]

Knowing how annoying re-running the line would be, I would try this as a quick test:

Craft a somewhat longer than needed phone cable with appropriate termination. Run it from your location in the kitchen across the floor and out to the garage where the termination board is. Make sure nothing else is connected in the garage to those terminals, and in the kitchen have only your base station connected (so, completely bypassing and unconnected to all home interior wiring). Test. This probably only takes a short time to do, presuming you have sufficient wire and termination jacks around. If this test works, then indeed something about the wiring in the house is the problem, including potentially some problem at other jacks around the house.

I've had mouse-chews at weird locations unrelated to where my phones actually were, causing shorted wires in the past. My bet is some problem like this, where the cable itself between your garage and base station is probably fine, but something elsewhere is causing the problem.

Good luck and keep us posted!!

 

[Marc_G]

Oh, and once my phones went dead. Thought it was a service issue. Turned out the housecleaner had rammed a vacuum cleaner into a jack, cracking it and leading to a short circuit.

 

[neil_w]

Craft a somewhat longer than needed phone cable with appropriate termination. Run it from your location in the kitchen across the floor and out to the garage where the termination board is. Make sure nothing else is connected in the garage to those terminals, and in the kitchen have only your base station connected (so, completely bypassing and unconnected to all home interior wiring). Test. This probably only takes a short time to do, presuming you have sufficient wire and termination jacks around. If this test works, then indeed something about the wiring in the house is the problem, including potentially some problem at other jacks around the house.

Even simpler: just take a phone into the garage and hook it directly to the incoming wires, while also disconnecting it from the rest of the house wiring. This will remove all extraneous house wiring from the equation. See if you get dial tone when hooked up that way. This is similar to what a service guy would do with a test set.

If that works, then you know that your service is working and for sure it's a house wiring problem. If it doesn't work, then it has to be a problem with your service.

 

[heada]

There are some cases were the the combo deals includes internet and phone together. When they do that, it isn't an old analog POTS phone but rather a digital phone signal that is actually carried over the internet line and then split out and converted into analog at the internet modem. If that is the case for you, you can't test anything before the modem as the signal is actually a digital signal and closely resembles a VOIP (Voice Over IP) connection. They make VOIP phones that would allow you to plug it into any network connection after the modem and some companies (Comcast) also made a VOIP phone that would connect directly to the coax cable and act as it's own modem.

If you have a true analog POTS connection for phone, your troubleshooting should continue as normal. If it is a VOIP phone or your modem is acting as a VOIP to analog gateway, then anything before the modem wont work with normal troubleshooting. If you do have a VOIP configuration, plugging the analog phone into the phone jack of the modem should remove any house wiring question and would identify the problem as the modem or a configuration with the service provider.

 

[Marc_G]

From reading the first post, it sounds like it is a digital signal that gets converted to standard phone system electronics, with a phone line that has been tested and found to be good from the modem going to the standard terminal board in the garage. So, we know so far the line is functional and a phone uniquely plugged in there works. So, something about the wiring beyond the terminal board is at fault. I loved Tom's idea about resistance thresholds but I suspect it is a more mundane problem than that.

 

[jqavins]

I can receive calls, but no dial tone.

Everyone seems to have ignored that sentence. If your phone rings, and you can pick it up and hold a conversation, then you can rule out all potential wiring issues. Lots of barking, wrong tree.

First question: are you up to date with the bill? (I'm only half joking.)

I have a combination internet/phone/cable deal (yeah, cable... sigh...) and so the phone eventually gets to the phone jack on my modem. The line from the modem, one from my combination printer/scanner/copier/fax (yes, fax! really!), and the jack from the kitchen met at a connection board in the garage right below my office. Last week the phone stopped working. So I brought the base station back here and plugged it directly into the modem. No problem. Keeee-rap, wiring? How do static connections go bad?

Maybe it's just me, but this was a confusing description. It does sound vaguely as if you're troubleshooting a VOIP system with an analog phone, as heada hinted. Could you draw a diagram, or describe the system more meticulously?

 

[Blast it Tom!]

Yeah, sorry - I really don't have time to draw something up, but @heada has it right. Coax is the only thing coming into the house, and I connect my conventional cordless phone to the phone port on the modem. The phone is not very old - I can pair cell phones to it via Bluetooth, for instance. But when the change-over from conventional land line was made, rather than re-wire everything, we ran a phone line from the modem down to the connection panel where the existing phone and fax were already attached. Red to red, green to green and it has worked for a good while. And as I said, everything checks for continuity and resistance. But I suppose my only real choice here is try replacing wires and phone jacks...

(Fax... land line... man what a dinosaur I am! Next I'll start posting on here with a teletype machine!)

I am going to call them again, though. Since all this started, our cell phones are dropping audio a lot. Like I said, they claim they have done "repairs and upgrades" in our area. And they don't tell you that you need to change some obscure setting in your router because of some cockamamie thing that they did.

 

[heada]

Re-running CAT3 (all that is needed for analog phone) is fairly easy. You should be able to tie the new cable to the old at the modem (using the embedded fiberglass string in the cable plus a few wraps of tape) and then pull the line at the phone end. That should pull new CAT3 cable from the modem to where the phone is and CAT3 cabling is dirt cheap. Put a new RJ-11 plug at either end and you've just replaced all the cabling. Matching colors doesn't matter as much as match wire positions in the RJ-11 plug.

Another option is to get a multi-base cordless phone. Place 1 base at the modem and connect it there and place the other base where you'd like the phone. The bases talk to each other to relay the phone call. That would eliminate any in-house wiring as an issue but would require you to replace the phone.

In the end, if you didn't make any changes to any wiring in the house, more than likely it is a configuration setting on the modem and a call into support should correct it. The thin copper wire in the CAT3 cable does get brittle over time (decades) but as long as you don't move it around, it should be fine. You can test that with a simple continuity test.

 

[rharshberger]

Re-running CAT3 (all that is needed for analog phone) is fairly easy. You should be able to tie the new cable to the old at the modem (using the embedded fiberglass string in the cable plus a few wraps of tape) and then pull the line at the phone end. That should pull new CAT3 cable from the modem to where the phone is and CAT3 cabling is dirt cheap. Put a new RJ-11 plug at either end and you've just replaced all the cabling. Matching colors doesn't matter as much as match wire positions in the RJ-11 plug.

Another option is to get a multi-base cordless phone. Place 1 base at the modem and connect it there and place the other base where you'd like the phone. The bases talk to each other to relay the phone call. That would eliminate any in-house wiring as an issue but would require you to replace the phone.

In the end, if you didn't make any changes to any wiring in the house, more than likely it is a configuration setting on the modem and a call into support should correct it. The thin copper wire in the CAT3 cable does get brittle over time (decades) but as long as you don't move it around, it should be fine. You can test that with a simple continuity test.

Most residential phone wiring if installed when the home was built is stapled every so often...by code...so simply pulling a new cable like it was in conduit should not work.

 

[heada]

Most residential phone wiring if installed when the home was built is stapled every so often...by code...so simply pulling a new cable like it was in conduit should not work.

You're right. I'm used to dealing with loose wiring or in conduit. If it's stapled, you're not going to pull new wire by tying on to the old. That'd really suck if that's the case.

 

[AllDigital]

my two cents, having resolved a lot of landline issues in my day:

1) if you plug your phone in at the modem and it works then it is a 99.9% probability that the issue is your wiring.
2) As you stated, it is only a two wire system, but many houses have tee off points going in parallel to lots of other rooms. The splices or faulty equipment plugged in is often the culprit. Unplug every device in the house that might be on a RJ45 jack and/or isolate down to a single hop and your known good phone.
3) If the wires are only in walls (not underground) and you have no mouse problem then it is more likely a bad RJ45 jack at either end. Those do go bad. I just had one go bad in my kitchen last year for no apparent reason. Don't test continuity on the back of the jack. Get a scrap piece of phone cord and cut it in half and plug it into the jacks on each end. One end shorted and the other open to continuity test. That will test the jacks and the lines.

It is possible it is more complicated -- like a wet or aged line, but that would be the exception, usually it is at a splice or termination point.

 

[jqavins]

I'm skipping some posts, so please pardon me if this has been covered. You've got an analog phone, and it was working with the rest of this setup, right? Have you tried a different phone? I'm still thinking that if you can receive calls then all equipment between the pole and the phone has to be good, and the problem has to be either the service or the phone.

 

[Blast it Tom!]

Well, thanks again all. Lemme see here, some repetition above, I'll see if I can hit everything:

Yes, @jqavins, the phone works fine when plugged directly into the modem. The phone, it would seem , is good.
@heada & @rharshberger, yes, the wire is stapled but I'd just "abandon in place" and run new on a parallel or similar path. I just don't want to!
@AllDigital, I've cut out extraneous connections, tested continuity and resistance (and it matched a value I calculated). It could be the wall jack, though I was able to get continuity "beeps" from both conductors to pins in the socket. From the basement up to the modem, both the fax and the phone would use the same segment of cable/connections, and the fax gets a dial tone. So the suspect section is from the phone to the connection board in the basement. It seems like it HAS to be that section, but it tests ok from a continuity/resistance standpoint. Although yeah jacks do go bad, it would seem I am testing the ones in my connection path.

Unless that wire from the kitchen down to the connection panel can test ok in my crude ways, but has all kinds of noise on it or other bandwidth issues (a crack though maybe 70% of the cross section? too small to affect resistance or continuity, but a pain for communicatio stuff).

I dunno, thanks guys, but it just seems that the kitchen jack or the wire itself has to be the problem. I suspect the cell phone audio is a separate problem; I'll try to get with them tomorrow.

 

[Marc_G]

Thanks for keeping us posted. This forum is full of folks that can't rest until the cause of a problem is known.

I agree, there's an issue with the line/jack into the kitchen. Good luck troubleshooting further!

 

[Blast it Tom!]

Thanks, Mark, I forgot to acknowledge you, and you helped out as well! Best to you!

 

[jqavins]

It seems like it HAS to be that section, but it tests ok from a continuity/resistance standpoint. Although yeah jacks do go bad, it would seem I am testing the ones in my connection path.

OK, this is just damn weird.

1. The phone rings.
2. You pick up the phone when it rings, and then audio goes in and out.
3. The FAX gets a dial tone, but the phone doesn't.
4. The phone does get a dial tone when plugged into a different jack, one that's only a cable away.

Three and four combine to mean the problem has to be in that piece of cable.
One and two combine to mean it can't be the cable.

The only possible answer is that you are having a recurring nightmare. Probably you don't even have a phone.

 

[Steve Shannon]

OK, this is just damn weird.
View attachment 527672

1. The phone rings.
2. You pick up the phone when it rings, and then audio goes in and out.
3. The FAX gets a dial tone, but the phone doesn't.
4. The phone does get a dial tone when plugged into a different jack, one that's only a cable away.

Three and four combine to mean the problem has to be in that piece of cable.
One and two combine to mean it can't be the cable.

The only possible answer is that you are having a recurring nightmare. Probably you don't even have a phone.

Is the phone you’re trying to use one of the old Ma Bell Cycolac phones with real bells or a new solid state type. Same question about your fax.
There’s something called the “ringer equivalence” that is useful when calculating the load of multiple phones to a circuit. Remember that they are all in parallel and telephone equipment must be able to be supported by the voltage and current capacity of the cable modem (or the nearest PSTN switch).
https://en.m.wikipedia.org/wiki/Ringer_equivalence_numberIt may just be that the modem you have cannot support multiple devices or that one or more of the devices you’re plugging in overload the modem.

 

[Blast it Tom!]

OK, this is just damn weird.
View attachment 527672

1. The phone rings.
2. You pick up the phone when it rings, and then audio goes in and out.
3. The FAX gets a dial tone, but the phone doesn't.
4. The phone does get a dial tone when plugged into a different jack, one that's only a cable away.

Three and four combine to mean the problem has to be in that piece of cable.
One and two combine to mean it can't be the cable.

The only possible answer is that you are having a recurring nightmare. Probably you don't even have a phone.

#2 is incorrect. It's the cell audio that's cutting out. I can receive calls in the landline when it's plugged into the kitchen jack, and hear them, but can't get a dial tone when plugged into the kitchen jack. It must be the wire or jack. Sorry for the confusion.

 

[Blast it Tom!]

Is the phone you’re trying to use one of the old Ma Bell Cycolac phones with real bells or a new solid state type. Same question about your fax.
There’s something called the “ringer equivalence” that is useful when calculating the load of multiple phones to a circuit. Remember that they are all in parallel and telephone equipment must be able to be supported by the voltage and current capacity of the cable modem (or the nearest PSTN switch).
https://en.m.wikipedia.org/wiki/Ringer_equivalence_numberIt may just be that the modem you have cannot support multiple devices or that one or more of the devices you’re plugging in overload the modem.

Well, if so, that's something new, because it worked fine until about a week ago. But thanks I hadn't thought about the parallel load thing.

 

[jsdemar]

It's easier to burn down the house and start over again.

 

[AllDigital]

 

[kuririn]

If it's working then it's a telephone.
If not then it's a telephony.

 

[jqavins]

If it's working then it's a telephone.
If not then it's a telephony.

Thank you for that. Now get back in your box.