The Administrator guide and the IVR section will tell you what IP address you get from your router.
This SPA2102 is not really a router, I would personally prefer only to have the WAN port on the SPA2102. Set the SPA2102 up on your LAN according to diagram on page 22 of theAdministrators guide. You can access the management GUI interface of the SPA2102 via the WAN ethernet port. This port is usually connected just like any other IP host on your Local Area network (LAN).
Determine the WAN IP address of the ATA device :
a. Connect an analog telephone to the Phone 1 or Phone 2 port on the ATA device. (You may not hear a dial tone. Continue to step b.)
b. Press **** on the keypad to access the IVR menu.
c. Press 110# to determine the Internet (WAN) IP address.
Use this information you hear to get to the management GUI of the SPA2102 via a Internet Explorer web page. http:// < IP address you hear>
I have found that the GUI is extensive, which makes the product very very flexible. But only put in the minimum information you need to get a SIP trunk working to your Internet Telephone Service provider (ITSP). You don't have to modify every GUI option you see. Best practice is less customization the better.
Use the Administrators guide to understand where to put the SIP trunk details from your ITSP. These options will normally be copied to the appropriate 'Line 1" or/and "line 2" Tabs.
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