Originally posted by *Saint*
Telephone line to modem>>modem to router>>router to computers.
If it was connected as you describe there, it would probably work -- although you don't really need the router (more about it later).
What your first screenshot indicates is that you have connected the Siemens SpeedStream DSL modem directly to the computer, using a USB cable. This type of modem has both interfaces -- USB
-- but you can only use one at a time. If you want to use it with a router, the first step would be to disconnect the USB cable.
Also, this type of modem functions as a router itself in its default configuration. This is confirmed by your second screenshot. While you could hook up another router to it and that should work for most purposes, a simple ethernet switch
would be more appropriate.
If you use a router in this kind of setup, the router's WAN interface should be set to use DHCP. This choice may also be named "acquire IP address automatically" or something like that. I recommend that you obtain and use a plain switch instead of a router, because the double NAT that occurs in such a setup is a nightmare for both UPnP and manual port forwarding (in simple words, while the Internet generally will work, some features will not).