Intermittent One-Ring Problem

[tmagg]

HELP! I am having an intermittent problem with my phones that is driving me crazy. The problem is that there are periods of time when someone calls, the phone rings once and then the party is disconnected. It may take several tries before they are able to get through. Whereas other times throughout the day there is not problem getting through and the phone rings normally. After 100's of calls and hours trying to isolate this problem I have come to the following conclusions:

1) I have 2 separate phone lines. One traditional from Verizon off the local loop and one VoIP from Sunrocket off a Telephone Adapater. Both are experiencing the same problem, so I have ruled out this being a service provider issue. In addition, I have tested each with a phone at the demarc and the problem does not occur.
2) I have 10 phones throughout the house primarily six AT&T 955 4 line intercom phones, and one 2 line Uniden Cordless. This issue first appeared when I added 3 AT&T 955 phones. I thought one of these must be bad, so I isolated them one by one. The first one I removed caused the problem to happen less (about half as much). But this was regardless of what phone I removed. When I removed 2 out of the 3 phones, the problem went away. I experimented and found out that removing any 2 phones solved this problem.
3) There is no static or other problems on either phone line during a conversation. I also double checked all of the wiring (as best I can since most of it runs through wall cavities, note half the phones are in a star wiring, and the other half are legacy daisy chained). I estimate I have about 1000 feet of wiring.

Any and all suggestions would be greatly appreciated. If you think the problem is I have too many phones and this is causing false seizures, please let me know if there is anything I can do boost or fine tune the line to support all of these phones. Also, any suggestions for tools to check/isolate this problem would be appreciated. Thanks! Tom

[suemarkp]

I don't know what happens if you exceed the design value for "ringer equivalence". Each phone should have a REN listed on it (and most new ones that have a separate power source have real low numbers like .1 or .2). I think the phone company designs for a total REN of around 2 or 3 and perhaps even less today since ringers are now electronic instead of bells. If the sum of all your REN's is above this, you need to find a way to reduce it. Can you turn off some ringers in individual phones? If they have lights that blink during ringing and no separate power supply, I'll bet the REN of each phone is high. If you need to support a higher REN, I'd call your provider to see if they have some equipment to allow all those ringers you need.

[tmagg]

Mark - thanks for the reply.

I counted the REN from each device:

6 ATT 955 at .3 REN each, Total = 1.8 REN
Uniden 2 Line Phone 0.7 REN
Answering Machine .2 REN
Fax Machine .3 REN

So it is about 3 REN. All of the devices have a transformer. I can turn on/off the ringers, but I have most of the ringers off (5 out of 6 ATT 955) for line 2 (business line) and line 2 has the same problem.

I have heard of devices that boast the REN, but they claim that it is to boast the ringing so that all phones ring. At this point, I don't even care if all or any of the phones ring, because even if I don't hear it, the caller will still be able to leave a message. Right now they are just getting disconnected. Do you think if I boast the REN it might take care of the disconnect problem also?

Is there any measurements I can take on the line perhaps with a voltmeter or ammeter while a call is being placed to determine if there is too low a voltage/current or an intermittent short in the wiring somewhere?

Thanks, Tom

[Mr T]

3 REN should be fine. Ive doubled that before under several phone companies with no problems. Todays ringers dont put near the load on the line that the old mechanical ones did.

Got a computer modem hooked up somewhere? Is your fax working? Ive seen a fax machine get zapped before and it would pickup and takeover the line whenever it felt like it. Could happen with a modem.

You dont have somebody sneaking in there and turning on call forwarding do you? (will get 1 ring then nothing) :D :D

I would start at your network interface, plug in a phone that is known good but not on your system now. If it works. Unplug all phones, and plug your phone into a jack in the house. If works Add a phone one at a time till the problem comes back. Try that phone at your network interface...to see if the phone is bad.

[suemarkp]

He covered some of that trouble shooting in his first post. But you could try to get a big phone tap or multi outlet (10 ports or more) and connect it outside at the NID. If you can plug in all the phones out there, but not inside the house, you may have a wiring issue. May want to try the FAX out there too.

But that doesn't make a whole lot of sense since you said it doesn't seem to matter which phones you take away as long as one or two are removed your system is happy. Does removing just the FAX help things?

I'd call your phone company and see if they have a recommended load for REN and ask them what happens if you exceed that.

You phone voltage is high when its on hook (about 50V) and low when off hook (I think I may have this backwards. I did post the voltages in a post a while back). You could monitor the line when the phone rings and monitor what's happening. But the ringer is an AC voltage superimposed with the DC, so it could be tricky to measure. YOu may also want to use an analog meter, or a digital with a bar graph, as you want to look for spikes or drops or something strange.

[mdshunk]

I'm gonna go out on a limb here and say that it's an equipment issue; specifically euqipment that is commone to both line. More specifically, a partial short that declares itself under the 90V, 20hz ringing voltage. A short will seize the line during the first ring, ringing stops, then line is released.

Now, I'm trying to figure what could be shorted in that manner that is common to both lines. There's not a lightning arrestor common to both of these lines, is there? Perhaps outside in the demarc? Perhaps installed by you?

If I had to lay money on it, I'd say it's an issue with the 955 phones. I had a mess of 925's in my own home, and they all failed in strange and different ways one by one. Perhaps they are "leaky" somehow (line to line), and when you get a certain amount of them on the same line, the leaks compound and give you line seizures.

[tmagg]

Thanks for all the replies. Here is what I did to try to further trouble shoot the problem.

Put all the phones in one room and connected them directly to the source. Line 1 (VoIP Sunrocket) still experienced the problem, but Line 2 worked fine. When I connected the house wiring, Line 2 experienced the problem again. I then isolated which leg in the house and it was the master bedroom run that was the problem so I rewired it. Now Line 2 was working fine, but I am still having the same problem with Line 1.

I decided to take voltage measurements under different number of phones conditions. I used a digital multi-meter. Here is a table:

Line 1 (VoIP Sunrocket)
Phones / Steady State / Off-Hook / Ringing DC / Ringing AC
1 Demk / 40.5 VDC / 5.7 VDC / 0.6 VDC / 58.2 VAC
4 / 40.5 VDC / 5.7 VDC / 0.6 VDC / 56.5 VAC
6 / 40.5 VDC / 5.7 VDC / 0.6 VDC / 55.5 VAC

Line 2 (Verizon Analog)
4 / 44.7 VDC / 5.5 VDC / 50 VDC / 82.5 VAC
6 / 44.9 VDC / 5.5 VDC / 50 VDC / 83.1 VAC

The bizare thing is that Line 1 DC volts goes way down on ringing whereas line 2 goes up! What should be the correct behavior? I dug the old Phaostron 555 analog meter out of the basement and re-ran the tests to see if I could see any jumpiness in the needle. The only jumpiness was in the ringing DC in that for Line 1 it oscillated tightly between around 0 and 1, and Line 2 around 49 and 50. I think there must be something wrong with my telephone adapter and I plan to send in a trouble ticket to Sunrocket, but judging from past responses, I'm not sure they will even know what a voltage meaurement means. I'm hoping the experts on this forum can provide some insight here. Thanks!

[suemarkp]

I can't explain the voltage readings... Does the problem on line 1 exist with just one phone, two phones, or only when you have 6 or more?

[tmagg]

The voltage measurements were for 1 phone hooked directly to the Sunrocket Telephone Adapter (they call it a Gizmo), and then 4 phones and 6 phones using house wiring. As you can see the measurements were about the same regadless of the number of phones. The main difference between the VoIP line and the Verizon line is that the VoIP line goes low to 0.6VDC when ringing whereas the Verizon line actually goes higher DC voltage (from the steady state). Do you know what the behavior should be or why there would be such a difference? Thanks, Tom

[suemarkp]

I don't know what the behavior should be, that's why I asked if you still have this problem with only one phone or you must have multiple phones connected to have the problem. If just one phone is connected and it won't work, I'd suspect your Gizmo (but try again with one phone of each model number you have). If multiple phones have to be connected to get the problem, it could still be the Gizmo or else one of the phone types may not be compatable with the signal the Gizmo is producing thereby wrecking things for all of them.

It appears that the Gizmo has different operating characteristics than the normal Verizon phone line. You may need an oscilloscope to look at it, but I still don't know what that would tell me. Perhaps the ringer tone is a square wave instead of a sine wave and one phone type doesn't like that.

[TraderDen]

hope you got this fixed, it sounds like mdshunk was the closest... that is if your ren value was correct. i have seen companies that will not guarantee proper operation with more than 5 sets on one line, regardless of ren value.

problems like this are usually a lot simpler than folks realize. instead of taking all of your phones outside or in one room or what not, you should use the meter outside at the interface. unplug the dial tone whenever you are having the problem at the interface. then look for a short across the tip ring of either line. then across each conductor... if you have a short when connecting both leads to any two conductors.. you have just found your problem. if you find no short whatsoever between any two conductors on your inside wiring, then test each conductor for a ground.

from what youve explained, i would guess that polarity is reversed on either your first or 2nd line(which explains why your needle was up on the first test and buried on your 2nd), and you will find the short between one conductor from line 1, and one conductor from line 2, tripping the line only when AC ringing voltage is applied.

sounds like you just have too many sets if there is no physical iw trouble though:wink: thats why folks buy phone systems