I understand that you want to know if you need the SlingLinks in order to get the connection between the Slingbox and the home router.
As a matter of fact, if the Slingbox (attached to the cable box) and the router are located in different rooms, you might need to use the SlingLinks. You only need to make sure that both rooms go into the same electrical circuit. Otherwise, the SlingLinks will not work since they will work with your home wiring system.
You can also use a wireless bridge as a second option. In this case, you wouldn't need to worry about the home circuitry, since the Slingbox will get the router's wireless signal through the wireless bridge. The following links will provide you with all the information about the SlingLinks and how they work.