Ooma Forums

Since the last post I measured the AC voltage from a known good ground and the Ooma grounding shield as described in other posts. I noted 2.25v from the Ooma to ground. This would be a good reason for a hum (or maybe a song). The customer care person is shipping another unit without any complaints from me.

Problem SOLVED: I connected a 100 microfarad electrolytic capacitor and a .47 ohm, 5 watt resistor in series from the Ooma USB ground shield to the ground on my power strip. All parts can be found at Radio Shack. I no longer have hum using a wired Plantronics S11 headset.

Glad that your solution worked! Now you may have to change your forum name

I'm having a similar problem when I use a headset on my 2-line phone. It's fine when I use the handset or the speakerphone, but with the headset, there's a very loud hum. Following the advice earlier in this thread, I tried grounding via the USB plug and the hum goes away completely. It seems like it might be a nice feature to include a ground plug or screw on the Telo, since this does seem to be a real problem. I'll go and buy a USB adapter plug and create a cable to allow me to ground this puppy so I can use my headset.

Cheers,

...scott

Glad I was able to help people.

FRET_BUZZ wrote:Problem SOLVED: I connected a 100 microfarad electrolytic capacitor and a .47 ohm, 5 watt resistor in series from the Ooma USB ground shield to the ground on my power strip. All parts can be found at Radio Shack. I no longer have hum using a wired Plantronics S11 headset.

Can someone take a photo of this set up and post it? I don't understand how to do this. Thanks.

thunderbird wrote:

jdurand wrote:I just found a fix for all but a very very slight hum, all the buzz is gone...

Get a USB cable and plug it into the USB port on the back. Connect the metal shield (outside silver part) of the plug on the other end of the cable to ground. You could use a clip lead to hook it to a metal computer case (if it's plugged in), or the mounting screw in the center of a grounded power outlet.

So, the problem is the AC adapter has way too much AC leakage. I didn't measure it but will be digging through my spare parts bin for a better one.

Let the forum know how you come out.

I had a buzz problem with a corded phone plugged into the Ooma Telo. The USB cable touching a ground spot silenced the buzz! When I connected a cordless phone the buzz disappeared anyway. No need to find a ground. Problem resolved.

I've had the buzzing noise from time to time. This time it's doing it again and I thought it might be electromagnetic interference. I noticed that when I hold the device with both hands, kinda shielding it, the buzzing noise was greatly reduced. I also checked with different wires to see if it was a bad connection and the results have not changed. But it does vary in sound when I wiggle the wires in the connectors on the ooma itself.
I can't put up with this noise anymore since it's louder than the people I'm talking to. Based off of what I've read on this thread and with my own testing that the ones with problems, unsolved, have defective units. The speaker on my unit died in less than a year of purchase so I have no doubt I got a crappy unit.
Unfortunately I don't have a spare 250 bucks to buy another one.

I resolved this, based on other suggestions by just plugging in a USB hub (that is grounded) into the USB port on the back of the Telo. Voila... buzz gone!

Thanks everyone- I was about to replace my AT&T 993 2-line phone before finding this solution. Plugging in a USB cable worked for me as well. I happened to have a wireless printer next to my Ooma that had an available USB port. If you don't want to deal with wires, screws, and manually grounding, you might try connecting your Ooma's USB port to a nearby device with an available USB port.