I have a customer with Ip Office 500v2 s/w is 8.1. Ocassionaly while on speaker the voice quality is garbled beyond comprehension. The phones are 9508, digital phones. Thus far just unplugging the phone and plugging it back in resolves the issue for a little while. Some phones are on a 16 station module, some on a 406 combo card. Happens randomly. Should we be looking into replacing cards. Years ago we used to think static electricity contributed to this issue. System is grounded and on a UPS.

Try going to Menu>Advanced Options>Audio>Echo Canceller = Off and save.

Ok, I suppose this is done from the phone because I don't see these options in manager?

Correct.