Step 1: Pick up the handset, and dial ****110#. Write down the IP address.
Step 2: Access the router's web-based setup page. For instructions, click here.
Click Applications and Gaming, and open ports 5060 - 5061 and 16384 - 16482. Note that the IP address in the box is just an example. You have to use the IP address of the PAP2 that you took note of when you dialed ***110#. For instructions on how to set up Port Forwarding, click here.