Check this out - a new wizard configurator http://obihai.com/pbxExtension.html
If you have a PBX (analog or digital, doesn't matter), you can extend the FXS port on the office PBX all the way to your home or other branch office.
All can be accomplished without ITSP subscription or external fixed static IPs. Just use 2 OBi110 devices, one in the office and the other at home.
I find this useful for small businesses.
If you try this, wouldn't you have to be on the same IP (VPN), or do you just mean during configuration?
Only during configuration do they both need to be on the same network.