D-link make good hardware but they're the one of the worst (if not the worst) brand name on documentation.

** This is a much simpler way to configure DVG-2001S instead of changing your computer IP to 192.168.0.x segment **.

How to configure DVG-2001S:

1. Connect it to any LAN port of your router;
2. **1 to get IP address of this ATA;
3. http://IP_Address_of_ATA/admin and login as admin/admin
4. Configure VOIP – both server&agent config (Refer the screenshots below)
5. Apply & Reboot

Here are two screenshots (It's from DVG-1402S but it's same for DVG-2001S). Please visit http://www.SunnyVoIP.com if you need more voip hardware.