I have a UC500 setup with four fxo lines which are forwarded direct to extension 201, occasionally incoming calls are dropped. It happens when the user answers the call, it connects but is then immediately dropped before they have a chance to speak. I have tried replacing the phone itself and the problem is still occuring so I don't think it's a problem with the phone hardware.
This problem is very intermittent maybe 1 in 50 calls, so i'm finding it difficult to gather debugging information. Has anyone had a similar problem before, or can anyone give me any ideas what this might be?