We just got 3 Primus TalkBroadband boxes. They work by just plugging into our LAN and then you plug in an analogue phone into the box to talk. Just like that and you can use it to call people (and receive calls).
They seem to communicate over port 2427 over the Internet. Primus has a VOIP server that registers our WAN IP associated with the Primus TalkBroadband boxes. Everything seems ducky on these phones until you talk for 5 minutes; the call gets dropped!
We tested this extensively and no matter what the calls will ALWAYS drop after 5 minutes of conversation. I talked to Primus support and they think that our firewall (Sonicwall Pro 3060) is dropping the connection due to some "safety" feature. I opened the firewall port to 2427 but it's no use...still drops the calls after 5 minutes. Does anyone have any ideas about this? Much appreciated!