we are using panasonic pbx system kx-ns500bx. now we started new remote site and planned to use two extensions there through vpn. already we have cisco asa 5505 ipsec vpn for using accounting application.(using vpn client for remote site) . can i configure vpn tunnel in the same device with keeping existing settings or we need to by extra devices for both locations.existing routers dont have vpn.please guide me to the correct solution.
Don't know about that specific model, but I haven't ever seen a VoIP phone with a VPN tunnel support. You likely need a dedicated VPN gateways both side.
For a quick, temporary solution you can: 1. use a software VoIP client on remote computers; 2. open SIP ports from WAN, only allowing access from the remote site's public IP (if it's static).