I have recently installed a CS600 with 120 Local IP phones. They are connected to new PoE switches. Customer has Plantronics CS70 headsets with handset lifters. There is alot of sidetone while communicating. Have tried adjusting transmit levels on the CS70 with no luck. Does anyone have a suggestion for a differnt headset? Or has anyone else experienced this?
Also when you turn the handset volume down to reduce sidetone you can't hardly hear the caller.

We have a 1000 recently installed also all Ip and have the same issue. Thought it was just on the bluetooth headsets and replaced some with Plantronics CS70 and CS50 and they are having the same issues. Even a few old wired Plantronics are doing the same. Working with Tech Support now. If you find a fix please let me know and I'll do the same.

Might have something to do with the Mic Gain, ESI can adjust ( so can Master Techs )

I wrote a half page dissertation on my ESI audio problems and erased it.

I'll simply say, ESI will tell you they don't support all models of headsets (even Plantronics)

I doubt it's going to be "an adjustment"

Two questions: "Is the mic "hot" after you've hung up with a caller"

What do the serial numbers on the back of the IP phones start with? (first 4 or 5 digits after any leading zero's)

Sorry I haven't checked in for awhile but what we had to do is to replace the IP phone with a digital phone on the exts. havingthe problem. The headsets then worked fine.