I have a OS-7400w 4.75 software all ip 22 phones about once a week I get OAS network error and oas card shuts down. The system has to be re-booted to get it back. Does anybody have any ideas?

Do you have a firewall between the Samsung and the network only allowing the ports the Samsung needs to get to it?

I had this on a site, turned out I had the oas card plugged into a 10mb switch port.