I have a new system to quote for a customer with multiple locations. Each location will have a PSTN gateway. I would really prefer not to have to sell/install a 3cx system at each site. The locations are connected via a meshed MPLS network, so no connectivity or NAT issues. Is there a PSTN gateway available that will allow the phones to register to it and make/receive basic calls in case the link to the 3cx system at the home office was down? Having to install a system at each location turns 3cx into a standard PBX rather than an IP phone solution. Some customers are willing to risk the site going down and having no available phone service but others are not. And having to sell a system for each site and then bridge them together is not cost effective and you loose out on the presence features (I know a fix to this is coming in version 11).