Hi brit20, the Slingplayer has an IR code fror the Comcast RNG150 receiver, just go to Watch.slingbox.com and run the configuration for the video input.
The Slingbox Answers Forum Moderator Team
Just to clarify something that is essential to getting the correct answer to you:
Do you have a slingbox pro, or a slingbox pro hd unit?
If it's truely the slingbox pro as you mentioned, you can NOT use it to get digital programming though the use of it's integrated internal tuner since it will only pick up analog stations.
The "slingbox pro hd" unit will pick up atsc and qam digital stations and would suit your needs as long as the stations arent encypted form your cable carrier. Any station that is encrypted can only be decrypted by their decoder setop box and thus would not be viewable on the slingbox pro hd's internal tuner.
You can however connect your cablebox to either the slingbox pro or the pro hd unit in order to gain access (watch and control) it in that manner. Assuming you only have 1 cablebox, this would limit you to watching the same content as a local tv user during simultaneous viewing conditions.