Thank you for using our answers forums. We are sorry to hear that you are having some issues with your Slingbox setup. With the 500, you would need to use component, composite, or HDMI so you would need a cable box with one of those 3 types of inputs. As for directly connecting the Slingbox to the router, there are a few other options. Please check out these articles for further help.
The Sling Moderation Team