I’m running freePBX 2.2.4 and I have a TDM400P card in the system going to 3 phone lines. My problem is that I keep getting calls dropped. They can last from 2 min to over an hour before they get dropped. After the call is dropped I can hang up the sip phone and then make the call again. Any help on where to look at where to find the problem and fix it would be great.