Thankyou for reading.
I have a new costomer with a home only 1 year old. He has an inconsitane buzz and hum on his phone lines. I have checked the grounding. Ran a new cat6 line around to the media panel and reduced the extra phones in the system. The cordless phones work next door just fine.There are harmonic filters on the variable speed domestic well, this has helped the satallite problems he had and the am radio. The inconsitantness of the problem has got me. Any help or sugestions would be great Thankyou
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telephone static and hum
3 posts • Page 1 of 1
Re: telephone static and hum
by Tomi Engdahl on Fri Sep 05, 2008 7:31 am
Here are some information what causes telephone line to hum and tips on solving hum problem on telephone line:
The telephone line
http://www.affordablephones.net/phoneline.htm
In the United States, the voltage applied to the telephone line to drive the telephone is 48 VDC; some countries use 50 VDC. Note that telephones are peculiar in that the signal line is also the power supply line. The voltage is supplied by lead acid cells, thus assuring a hum-free supply and complete independence from the electric company, which may be especially useful during power outages.
A telephone line is balanced feed, with each side equally balanced to ground. Any imbalance will introduce hum and noise to the telephone line and increase susceptibility to RFI.
The balance of the telephone line is known to your telephone company as "longitudinal balance." If both impedance match and balance to ground are kept in mind, any device attached to the telephone line will perform well, just as the correct matching of transmission telephone lines and devices will ensure good performance in radio practice.
How to Fix a Hum in a Phone Line
http://www.dannylipford.com/diy-home-im ... hone-line/
There are a number of things that can cause humming or static in a phone line including a short in the wires, a defective phone, interference from power wires or light fixtures, and a signal from another electrical device. Here how to go about isolating and repairing the problem:
* First, check to be sure the hum is coming from inside your home by opening the telephone interface box, disconnecting the test jack, and plugging a corded phone into it. If you still hear the hum, then the problem is with the phone company. If it stops, the problem is inside your house.
* If it’s inside, plug the house jack back into the interface box and unplug each phone in the house one by one while listening in on another extension. If the hum disappears, the problem is with the phone you unplugged.
* If the hum persists, disconnect each set of wires one by one from the terminals in the interface box, and listen on an extension until the sound stops.
* Once you’ve isolated the problem wires, check the connections at the jack, and try unplugging any electrical devices nearby that could cause interference.
* If you’re still having problems, hook the other two color coded wires in the cable to the jack and interface box.
* As a last resort, permanently unhook the defective wires at the interface box and run a new line from the interface box to the jack.
Phone System Tech Support » Telephone Services » Telephone Service » Hum on POTS line
http://www.sundance-communications.com/ ... 000024;p=0
A butt set really isn't all that much different than a regular telephone. There is some circuitry inside that will allow the technician to make sure that a telephone line isn't wired "backwards" and maybe some built in circuitry that allows the technician to test a telephone line with DSL service without causing the DSL signal to drop.
Hum is sometimes caused when one of the two wires that make up a telephone line are broken or if there is a partial ground condition on the telephone line.
To determine if the problem is being caused by one of the telephones, have your parents unplug all but one of the telephones and then make a test call. If there is hum, disconnect that telephone and connect another telephone. If no hum, either the first telephone or the wiring to that jack is bad.
If you still hear the hum, then it would appear that Qwest still has a wiring issue that needs to be resolved.
If the house is an older one, there is a slight chance that there's a dial light transformer on the premises from the old days. These were used for Princess and Trimline phones in the 1960's and 1970's. They were wired to a separate pair of wires (usually the black/yellow) in quad wire. This induced 10 volts AC into a piece of wire that is not twisted pair right along with the dial tone.
These transformers have also been know to overheat, and cause fires, giving another good reason to remove them.
SBC's wiring is 99% twisted-pair, with the possible exception being the final drop wire to the house. If the technician changed the address to another pair, then it's safe to assume that the problem is in-house. Most newer phones are much more sensitive and will pick up the slightest imperfection in the inside wiring.
By plugging a regular corded phone in at the NID and still hear the hum, you've eliminated the inside wiring. Not sure why it wasn't heard when the Qwest tech was there the first time but plugged directly into the jack in the NID the noise has to be coming from the Telco network.
If you really want too you can diagnose it for them.
Check on hook Tip to Ring AC Voltage it should be <.5 Volts AC
Check on hook Tip to Ground AC Voltage it should be <.5 Volts AC
Check on hook Ring to Ground AC Voltage it should be <.5 Volts AC
If you have any Higher than .5 Volts AC then your getting AC induced or introduced into the line. Tell your phone company you have an imbalanced line.
--------------------
Woody Asher
Datacom Cable, LLC
Manchester, KY
The telephone line
http://www.affordablephones.net/phoneline.htm
In the United States, the voltage applied to the telephone line to drive the telephone is 48 VDC; some countries use 50 VDC. Note that telephones are peculiar in that the signal line is also the power supply line. The voltage is supplied by lead acid cells, thus assuring a hum-free supply and complete independence from the electric company, which may be especially useful during power outages.
A telephone line is balanced feed, with each side equally balanced to ground. Any imbalance will introduce hum and noise to the telephone line and increase susceptibility to RFI.
The balance of the telephone line is known to your telephone company as "longitudinal balance." If both impedance match and balance to ground are kept in mind, any device attached to the telephone line will perform well, just as the correct matching of transmission telephone lines and devices will ensure good performance in radio practice.
How to Fix a Hum in a Phone Line
http://www.dannylipford.com/diy-home-im ... hone-line/
There are a number of things that can cause humming or static in a phone line including a short in the wires, a defective phone, interference from power wires or light fixtures, and a signal from another electrical device. Here how to go about isolating and repairing the problem:
* First, check to be sure the hum is coming from inside your home by opening the telephone interface box, disconnecting the test jack, and plugging a corded phone into it. If you still hear the hum, then the problem is with the phone company. If it stops, the problem is inside your house.
* If it’s inside, plug the house jack back into the interface box and unplug each phone in the house one by one while listening in on another extension. If the hum disappears, the problem is with the phone you unplugged.
* If the hum persists, disconnect each set of wires one by one from the terminals in the interface box, and listen on an extension until the sound stops.
* Once you’ve isolated the problem wires, check the connections at the jack, and try unplugging any electrical devices nearby that could cause interference.
* If you’re still having problems, hook the other two color coded wires in the cable to the jack and interface box.
* As a last resort, permanently unhook the defective wires at the interface box and run a new line from the interface box to the jack.
Phone System Tech Support » Telephone Services » Telephone Service » Hum on POTS line
http://www.sundance-communications.com/ ... 000024;p=0
A butt set really isn't all that much different than a regular telephone. There is some circuitry inside that will allow the technician to make sure that a telephone line isn't wired "backwards" and maybe some built in circuitry that allows the technician to test a telephone line with DSL service without causing the DSL signal to drop.
Hum is sometimes caused when one of the two wires that make up a telephone line are broken or if there is a partial ground condition on the telephone line.
To determine if the problem is being caused by one of the telephones, have your parents unplug all but one of the telephones and then make a test call. If there is hum, disconnect that telephone and connect another telephone. If no hum, either the first telephone or the wiring to that jack is bad.
If you still hear the hum, then it would appear that Qwest still has a wiring issue that needs to be resolved.
If the house is an older one, there is a slight chance that there's a dial light transformer on the premises from the old days. These were used for Princess and Trimline phones in the 1960's and 1970's. They were wired to a separate pair of wires (usually the black/yellow) in quad wire. This induced 10 volts AC into a piece of wire that is not twisted pair right along with the dial tone.
These transformers have also been know to overheat, and cause fires, giving another good reason to remove them.
SBC's wiring is 99% twisted-pair, with the possible exception being the final drop wire to the house. If the technician changed the address to another pair, then it's safe to assume that the problem is in-house. Most newer phones are much more sensitive and will pick up the slightest imperfection in the inside wiring.
By plugging a regular corded phone in at the NID and still hear the hum, you've eliminated the inside wiring. Not sure why it wasn't heard when the Qwest tech was there the first time but plugged directly into the jack in the NID the noise has to be coming from the Telco network.
If you really want too you can diagnose it for them.
Check on hook Tip to Ring AC Voltage it should be <.5 Volts AC
Check on hook Tip to Ground AC Voltage it should be <.5 Volts AC
Check on hook Ring to Ground AC Voltage it should be <.5 Volts AC
If you have any Higher than .5 Volts AC then your getting AC induced or introduced into the line. Tell your phone company you have an imbalanced line.
--------------------
Woody Asher
Datacom Cable, LLC
Manchester, KY
- Tomi Engdahl
- Site Admin
- Posts: 1839
- Joined: Mon Oct 20, 2003 6:15 pm
- Location: Espoo, Finland
Re: telephone static and hum
by redgecko on Sun Sep 07, 2008 10:21 pm
Thank you, for the suggestions I wil give them a try.
- redgecko
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