I have bad quality voice on my wireless Cisco phones.
I found something:
If I enter "show int counters errors" on the switchs where are connected my WLAN controllers, there is a lot of "UnderSize errors", and there are more and more.
My controllers are connected to this switchs by Fiber and SFP transceivers (GLC-SX-MM). The fibers are 1 meter long. The 4404 controller is connected by link aggregation on 2 Gb ports.
Do you know this "undersize errors"? Because during a call, there are lost packets...