Noisy 4620's

[ronfitz1]

S8300/g700 + midspan power. I have about 15 phones that intermittently "hum" both on and off hook. I looked in the ceiling and all cable runs are clear of lights and any other potential interference. I eliminated the midspans using local power and I've turned off all cell phones/Nextel/Blackberries. All firmwares are up to date. Still the hum.

Any help would be great.

Thanks