I have a 100 running v1.34 software. Problem is when the receptionist answers a call she hears a screech, she said it kind of sounds like fax tone. I've heard it once and it sounds like two microphones too close together. I also have a different customer that I have a call center setup. Same thing. 100 with 1.34 and everyone who answers gets this weird screech. Called tech support with no success. Anyone have any ideas? I've adjusted the volume setting on the phone and reset the system, switched out phones. Any help will be greatly appreciated.