I have 2 LANs, they are VPNed and have VoIP functionality.

I need to be able to route a call from LAN 1 to a PSTN line at LAN 2, and of course, vice versa.

Ideally it would be a simple box to plug into our router with a plug for the phone line, but in reality I am finding it difficult to lay my hands on something that will do this. Most gear only offers PSTN as a 'backup', so it will only be used in emergencies.

All help appreciated guys.