I have an IP Office version 11 at one site and an older NEC key system at another site. They want to keep the NEC system in place but would like to have a way to connect easily when needed. My thought were to connect sites with VPN tunnel and use maybe a Patton ATA connected via SIP to the IPO and connect the analog side of the Patton ATA to a trunk port on the NEC. That way when you call the extension from the IPO side the line rings on the NEC, or from the NEC side you can pick up the line and call an extension on the IPO side. Is there a better way to accomplish this? Hope i'm explaining this well enough.