Scenario: FRITZ!Box is not only a great router for home fibre installations, but it also has a built-in SIP server that works with 2talk and Grandstream IP Phones! Products Used: FRITZBox 7490 Gigabit 802.11ac ADSL / Fibre Wireless Router Grandstream GXP2160 6 Line IP Phone Step 1: Login to your FRITZ!Box and navigate to Wizards > Manage Tele...