Getting rid of the phone buzz?

April 12, 2007 8:18 AM

My phone has a loud buzzing noise. When I touch the screw on a lightswitch plate, sink faucet or a metal lamp, the buzzing stops. What is happening – and more importantly how can I use the phone without having to ground myself?

My phone service is through my cable provider. The cable comes into the house, splits into a box for internet (cable "modem") and into another box for my phone service. My phone connects into my "phone box" with a standard telephone wire.

I did some research and my hum/noise problem sounds like a ground loop – except that my phone, internet modem, router, laptop, etc. are all not grounded. (They have only 2 prongs. But maybe the cable is grounded.)

Also, confusing (to me) is the fact that the problem goes away when I am grounded. What does me being grounded have to do with my phone?

posted by kamelhoecker to Technology (4 answers total)

Well, first of all, there are two different types of ground you're thinking of here. Let me assure you that there is certainly a 'ground' in each of your devices. It's known as the - or negative side of the supply. Without going into an electronics tutorial, you need to:

1) Try another phone as a test
2) Contact your provider for a new box, yours may be defective

If this is a cordless (you didn't specify), then the rules change completely.
posted by IronLizard at 9:59 AM on April 12, 2007

Cable is supposed to be grounded, usually. Try "grounding" the system: try connecting a thin wire between some metal point on your phone box to the nearest outlet plate-screw or water-pipe.

I don't think this would be risky but standard caveats apply. If you are at all unsure about doing this, find an expert friend or hire someone qualified.
posted by Artful Codger at 3:16 PM on April 12, 2007

Find your phone junction box in the cellar and tighten the screws where the wires are connected.
posted by Ferrari328 at 6:23 AM on April 13, 2007

Response by poster: Thanks for the suggestions so far.

I actually called a service technician (before i figured out the grounding myself trick) who basically said "dunno". There was no buzz on his test phone, so that was the extent of his help.

My phone didn't buzz before. I can accept that I need a new phone, but I'd like to still understand the problem so that I don't buy a new phone and find I've still got buzz.

Artful Codger: I tried wrapping a wire around the metal part of a coax cable end and connected the wire to the metal part of an electrical box. No change. (but when i touch the metal on the coax, the buzz stops. same as if i was touching a metal lamp or a faucet. So i guess that shows the cable is grounded.)

Ferrari328: There are no screws. The junction box is a box that connects to my cable hookup. The phone connects to the junction box. (I assume it's a VOIP thing, but this has nothing to do with voip sound quality issues. It always buzzes.)

I still can't wrap my mind around why the phone buzzes if affected by me being grounded. The phone is plastic - so how can a "grounded person" make a difference to the circuit inside the phone? (yes, the whole world of electons mystifies me.)
posted by kamelhoecker at 1:21 PM on April 13, 2007