Buzz noise on OBI100 not OBI110

[Judgeless]

I now have 4 OBI110's and just added an OBI100 that I am going to use when I travel.

All the OBI110's work perfect.  The OBI100 has some buzz on the line.  Is there a way to filter this out?

I did a test.  I put all 5 devices next to each other and plugged the same generic phone into each one and dialed a number.  When you do this get silence until you dial a second number.  Some OBI110 have a little more back ground buzz then other but it is not noticeable.  The OBI100 is very noticeable. Do I have a bad unit?  Do all OBI100's have this issue? Is there a simple fix?

[RonR]

I've got OBi110's and OBi100's in service here and don't get any buzz.

What do you mean by dialing a second number?:

"When you do this get silence until you dial a second number."

You don't have a cell phone anywhere in the vicinity, do you?  They are notorious for interfering with all kinds of electronic equipment.  Routers and cordless phones in the vicinity are also possible culprits.

[Judgeless]

What do you mean by dialing a second number?:

"When you do this get silence until you dial a second number."

You don't have a cell phone anywhere in the vicinity, do you? 

When you pick up the phone you get a dial tone.  When you press a number the dial tone stops and you hear silence.  During the silence you can here the buz very well.

I do not have a cell phone in the vicinity.  I wonder if I should just send this unit back. 

[RonR]

Take the OBi to a totally different area and connect nothing to it but a simple corded telephone and its power supply.  If you still get a buzz once you break dialtone, it's almost certainly originating in the OBi or its power supply, which you can swap out to eliminate.

[Judgeless]

Today I isolated the unit by just plugging in a phone and the power supply into the OBI100.  It still had the buzz.

I noticed that the OBI110 and OBI100 use the same power supply so I tried a supply from an OBI110 on the OBI100 and it still has the buzz.

Do you think I should send back to Amazon or try sending it back to OBI?

[RonR]

Do you think I should send back to Amazon or try sending it back to OBI?

If you also took it to a different part of the house to rule out any possible interaction with wireless phones, routers, computers, etc., it sounds like a defective unit.