As I've only been studying voIP technologies for several days my terminology might be incorrect and/or my understanding. Please feel free to educate me if I mispeak. I've been able to get the system up and running with three softphones (one on a laptop, one on a pocket pc, and one on a standard computer). In the future, I'm going to use a PAP2 and hook up my regular phones. I will not have a PTSN, so I won't be using a FXO Gateway. I was thinking that it would be convenient to set up the pocket PC in a way that allowed me to jump networks and still remain connected as an extension. To clarify by example: I sit in my home office and am connected to the network that the 3CX server resides on. I want to be able to go to the coffeshop down the street, connect to their network and still appear as an extension. I was wondering if I could just use DDNS and type the domain name in for the info, so long as I had my home office router forwarding the appropriate ports, and then restrict this type of connection by the MAC address of the NIC in my pocket PC... That's all.... great product, fun stuff to play with..... thanks!