Recently when I make outgoing call from SP2 (I configured it for Rynga to call internationally), my calls will be dropped after 30-60 seconds. It happens always. My SP1 is fine. This is not router problem because the calls still drop when I connect the obi100 box directly to cable modem without router. Think this is obi100 box problem.
It's unlikely this a hardware problem.
Try swapping the providers on SP1 and SP2. If the problem stays with SP2, it might be a hardware problem.
If the problem moves to SP1, it's likely your provider or a configuration issue.
I tried to use voice gateway (**3) to call international and switch to SP1, I also dropped.
IN summary, call by SP1 no call drop, call by SP2 has call drop in 30 seconds, call by voice gateway from SP1 or SP2 with **3 has call drop in 30 seconds. I observed many packets dropped in SP1 and SP2.
The problem get resolved after many test. I enabled IPSEC ALG port forwarding in router (westell 7501), the outgoing calls do not drop anymore. I believe Rynga in my SP2 uses some encryption which cause the problem in my router.