Telephone Problem


  #1  
Old 08-12-03, 07:35 PM
busterm
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Telephone Problem

No problem on outgoing calls. Incoming only rings once then caller hears static. Everything ok on my side of service box so problem must be in wiring because problem persists when all devices are disconnected. I by-passed security system and all worked well for a couple times then problem resurfaced.

I guess I have a bad connection somewhere on the red wire but would definitely appreciate some trouble shooting tips. Thanks.
 
  #2  
Old 08-12-03, 08:13 PM
R
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Here is my guess as to what your are seeing -- it is called a showering line. What happens is that there is a part of the circuit that is probably around 1K-5K ohms on the line (probably tip to ground). What is happening is that the the ring current causes the resistance to drop (the ring is a 60-90V AC signal on the line which causes the phone to ring).

The resistance drop is seen by the central office as an off-hook -- hence the ringing stops. Some central office switches have a different circuit that is put on the line when the circuit is off-hook, and that circuit sees the resistance on the line as an on-hook, and thus disconnects the line from house -- the other guy hears silence or noise in this case.

Houses are usually wired with the lines all going to a central place, and then are put together to the phone line. I would start there, and see what resistance you see. Without anything connected, the resistance should be very high -- over 100K ohm. Start disconnecting the lines and checking them individually for low resistance (in the 1K to 5K range). Do them one at a time so that you don't get them mixed up.

Again, this is just my guess at what you are seeing, but it is a place to start.
 
  #3  
Old 08-14-03, 04:07 PM
busterm
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Bob H, thanks for your expert advice...you solved my problem. I have two 4-conductor wires. One had low resistance on both tip and ring. Fortunately it is the downstairs feed which is very accessible. I'll probably run a new wire instead of searching for the short. I know it is in the wire because the short is there when the wire is disconnected from the jack wall plate. Thanks again!
 
  #4  
Old 08-31-03, 10:10 AM
busterm
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tel problem back!

Problem with incoming calls is back. Systematically eliminated devices so must be internal wiring problem other than showering line. Oddly I do have 8 voltsAC tip-grnd and ring-grnd. Can't imagine what is generating this voltage.

Can someone tell me what resistance and voltage I should have across tip, ring and ground? This is a wierd problem.
 
  #5  
Old 09-02-03, 08:23 PM
R
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The phone company supplies 48V on the line -- that powers the phone and allows the switch to detect off-hook. However, depending on the length of the wire from your house to the switch, you will see a lower voltage at your house.

If I remember right, it is -48 tip to ground (but that may ring to ground).

If you can separate the wiring to teh switch from the wiring in your house, you can tell if the AC is from your house or from the outside. If it is from outside your house, it may be something that the phone company needs to fix -- however, I don't remember where the threshold is to call it an error -- 8V AC seems low to actually cause problems.

If the AC is from inside your house, it is probably an induced voltage from running too close to AC wiring in your house. Same procedure to isolate the problem -- and the solution would be to move the wire aware from AC lines -- did you run it along AC wires?

Bob H.
 
  #6  
Old 09-03-03, 05:28 PM
busterm
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Bob H, The 8VAC is on both lines in my house when disconnected from the telco at the NID. I agree it must be induced voltage. One line is original installed 13 yrs ago during initial construction. Other line I installed 6 years ago. The one I installed is right next to an electric line for a few feet. Can't tell if original line comes close to any electrical wiring. Neither line has ever caused a problem. My guess is that this low voltage has always been there and is not my problem, but I am grasping at straws. For the last several days I have kept my computer and security systems isolated from the phone lines and replaced one phone which had been acting a little wierd. So far all is well. I will wait a couple weeks then add back devices one at a time to see it problem recurrs.

Telco supplied voltage is 44-45VDC at my NID.

Thanks for your help and interest.
 
 

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