I am comming back almost a year after for the same matter.
The installation of an A800 with an A1200 on the same machine when the buffer re-sync fault appears is HIGHLY NOT Recommended. The pbx presents problems. The most common is a sudden loss of one of the extensions. E.g. No tone would appear on the extension while asterisk sees all channels just fine. Another is the drop of the call. Bad call quality etc.
The problem solved when i removed the A800 and installed 8 IP phones. The pbx works just fine without any errors.
I don't know if Openvox recognizes this problem and if there is any other solution.
This is due the pci bridge of A800P, this chip have some bug when work with PC. we have a full new design A810/1610/2410 that solved the hardware bug through a full new design of fpga based pci bridge. if you meet such trouble, please use our new model.