Hum on the line

What is the primary cause of an overpowering hum on the line? The hum is so bad that the other party can barely be heard and it is on all the phones (corded and cordless). I am thinking a short of some kind but would like to run it through here first.

Leslie

 

It could be a partial short, or a bad phone/phone cord/jack, or even a line laying next to a highvoltage cable.

The quick dirty test is to plug a phone that you know is good into the test jack on the NID where the incoming line is connected to the house wiring.

If it's present there, then the problem belongs to the telco company. If it's clean there, then start by unplugging all of the house phones, and plug them back in one by one. It's not uncommon for aging phones, especially inexpensive cordless ones, to start doing this.

Unless there's something really odd going on, you will narrow down your suspects pretty quick.

 

The hum is in the NID test jack as well, does that mean a loose connection in the telco side of the NID or something else down the line?

 

if the hum is still apperatn when testing at the jack in the ned then its up to the telco to repair it

thats the point of the nid test jack ..to determine weather the problem is yours or theirs

 

Yup, what he said. It's your telco providers issue. Sometimes this happens when one of their pedistals gets water infiltration after a bad rainstorm. It wouldn't surprise me if your neighbors aren't having problems as well.

 

Appreciate the help. The telco said they would be out sometime between noon Friday to 6 pm Monday, since they didn't need access to the house to check the problem. Thanks again

Leslie

 

I too have just developed a phone hum on my lines. I checked it at the NID with my old fashon phone with no power cord and it is fine. I disconnected all the phones and connected up various phones by themselves and it was still there. I disconnected all the power cord phones both the phone line and the power lines. I then reconnected the one old fashon phone with no power cord and it still had the hum.

A few years ago I did an addition and added more phone lines. I ran them all to a terminal block near the NID entrance to the house and connected them up there. I also connected the old phone lines to the TB also. That was 3 years ago and everything has been working fine until now. There have been no changes recently that I can think of that could effect it. we did have an unusually heavy rain storm but the NID is sheltered under an overhang and the outside line works fine. Before I start tearing into walls etc. is there anything else that could cause this problem?

Ron

 

Could it be interference? I once had a cordless phone (900 MHz Uniden) that picked up a hum from light dimmer switches. I have since replaced the dimmer switches with RFI-filtered types and replaced the phone as well.

My new cordless (a 2.4GHz VTech) now gets crackly when I'm near my wireless router, and goes away when I move away from the router. I figure if the router can interfere with my phone, then my phone could be interfering with my router.

So I guess it's time to replace the phone again, maybe with a 5.8GHz? This is driving me nuts. Where's the FCC when you need them?

 

since you ran all the lines to a terminal block unhook them one at a time and see if you can isolate the hum to one line.

you also can get a hum if the line is unbalanced if one of the strands in the cable pair is longer than the other

have you spliced any of the cables by chance ?

 

Mango Man and Razz

I was able to isolate to problem to one section of the lines by disconnecting various lines at the terminal block. As a result I have restored service to all but 2 rooms. I do have access to part of the effected lines that run thru the joists of the new addition I put on. I still don't know what is causing the problem. Yes in this section of wiring some lines were spliced together. This is where I spliced the old house wiring with one room of the new addition. All the other new rooms (4 in all) had seperate lines run to the terminal block. I did video tape all the wiring before I put up the drywall. I was able to go back and see the splices in the video and where they are at. It is the only section of phone wiring with splices.

Ron

 

You could try switching the used pair of wires in the bad section. IE: if you used the White/Blue pair, then you could switch to the White/Orange pair and give that a try. Who knows, you may get lucky and find a pair that works. It's definitely much easier than tearing out sheetrock.

Good luck!

 

safewatch

That is a very good idea and it is easy for me to implement

Ron

 

I have a similar problem with hum. The kitchen phone had always had a very low level "whine"; you could hear it but talk over it. The cordless phone and answering machine attached to the same wire pair by a 3 way modular jack did not have this whine (replaced the jack, still there). One day, our phones just stopped working. No event like lightning strike or work done on the wiring to explain it. I went to the NID, the builder had 3 large bundles of wires coming from it. I figured it must be a short so I swapped color pairs like suggested below, started rewiring all the jacks to match. The phones worked again, but the whine in the kitchen was there just the same. I rewired the jack in my sons room and plugged in a phone (he had not had one there before). That line (tried other phones) has a very loud AC hum. Tried a DSL filter (we don't have DSL, cheap so tried it anyway), tried a snap-on choke at various points, tried a 1:1 audio filter transformer. Nothing makes the hum go away. I noticed that the bundles run right by the electrical panel, could be it; I suppose there is no way to shield them? Rerouting isn't easy. One reply mentioned differences in wire length (unbalanced) as a cause of hum: just how much difference is required to case this? Half an inch, half a foot, or ? Thanks.

MH

 

I have got hum- problems 3 times.
1: A new telephone bought abroad, probably bad quality.
2: A nice 1980 telephone fully electronic, witch is an early stage of theese. Probably a cap drying out.
3: Somtimes a lot of hum on the telephone near the PC.
Changing telephone did not change it, and it was not always there. moved the cord between telephone and outlet to oposit side of the desk, (away from some adoptors/transformers) and the humming is almoast gone, and not a problem any more. Probably one adaptor with a bad making noice. Its not disturbing my Skype adaptor.

dsk

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