STEP 1 You must first determine the IP address of your device.
To do this, press the Paper "button" followed by the number 9. This will take you into the network settings. Option 2 on the display will show you the phone's current IP address
Go to any browser equipped computer on your network and enter the address: http://<IP ADDRESS>/
(where <IP ADDRESS> is replaced by the address that was given to you in STEP 1)
Click on the "Admin Login" button near the top right side of the screen, then click on the "Ext 1" tab.
You need to modify only a few parameters from the factory default. They are listed here:
SIP Port: 5060
Register Expires: 3600
User ID: sip789xxxx
STEP 5 Make calls!