Looking for a solution to allow SIP phone to call out FXO line.

[Anonymous]

I currently have a remote analog POTS line that needs to be accessible to our HQ. We would like to be able to take a SIP phone line and have it register to a device that has the analog line connected to the FXO port. The catch is our SIP phones are on a completely different network than where the device will be located so it will be layer 3 connectivity. Can this be done with the Netvanta 6250? If so is there a config guide I can use to get this operational?

[jayh · Accepted solution]

As long as the phone network can reach the 6250, then a SIP phone can register to it. The fact that the traffic traverses a router along the way isn't itself a problem.

Gotchas of making this work include NAT between the phone and the 6250 by an external device (try to avoid this if at all possible), configuration and provisioning of the phone itself. If the SIP phone will also connect to another VoIP system, then things get more complicated, including (this isn't an exhaustive list...)

• Is this the only device to which the phone will register?
• If not, do you want a separate line button on the phone for it?
• How is the SIP phone going to be configured (tftp/ftp/http/https server, etc.)
• Are the dialplans compatible with the other system?
• 911 concerns if the phone is remote.