If your cable box only has composite ports (yellow, red, and white) and HDMI, your right that only leaves you with a stander definition source. I believe that the best way to get a HD video would be to get a HDMI adapter. We do have a link to one on our website, that we do support using. The link below will take to our accessories page, where you'll find the adapter.
Hope that information helps!
There seems to be an issue with HD copy protection or HDCP. Apparently, all components (cable box, sling box and the HDMI cables that connect between the cable box, SB, and the TV, all have to support the ability to disable HDCP. If they all don't, then you have a problem. It sounds like the SB devices do not support disabling of the HDCP. My guess is that is that may be the purpose of the adapter. It would be good if folks from Slingbox could confirm what is really going on here with respect to HDCP.
Hi, I had the same problem with our new Comcast X1 system. I tried connecting my SB 500 to the main cable box that has the built in DVR. It only has HDMI and the Red/White/Yellow jacks. No component (R/G/B) inputs. So I tried connecting with just the HDMI cable. The slingbox would not work with just the HDMI cable. Luckily, I have two other cable boxes in the house that do not the built in DVR. Both are Comcast (Samsung) RNG150N boxes. Those boxes do have the component (R/G/B) jacks. So I connected the SB 500 to one of those boxes instead. I used the HDMI connection, the component (R/G/B) connection and the Red/White audio connection. This worked. So, not sure if you have a second box in the house for another TV. But it appears the system doesn't work if you only use the HDMI cable. If you only have one box in the house, I'd bring it back to the cable company and ask them for one that has component inputs.
I got a new cable box, and it doesn't have enough cable inputs for my Slingbox 350. There are no inputs to connect the red, green and blue HD video cables, There are only audio inputs and one yellow video input. So I have to connect it as a SD instead of HD (even though the box and TV are both HD). Does anyone know how to solve this problem?