Many cable operators around the country are reclaiming analog space (separate from the over the air digital transition). If you have a cable set top box, nothing should change. If you connect coax out of the wall to an old analog set, you MAY need a Digital Terminal Adapter, DTA for short from your cable company. Most will make this available free of charge.
What you will need for optimum functionality and how to connect it:
1. Coax cable from wall to DTA RF IN
2. cable from DTA to existing Media Center tuner
3. Media Center Remote control
4. Either a built in eHome Receiver or external USB eHome receiver
5. IR two way blaster cable. The DTA adapter comes with a remote and an IR extender. Do NOT use the IR extender to plug into your eHome MCE receiver.
6. Carefully position the sticky adhesive on the LED on the end of the blaster cable over the receiver eye on the front of the DTA. Plug the other end into the port for you eHome IR receiver or the port on your USB eHome receiver.
7. The DTA has a switch on the back to set it to Ch3 or Ch4, for purposes of TV Setup on MCE this setting should not matter.
Now you are ready to re-run TV Setup. Open Media Center, Navigate to Tasks/Settings and then run TV Setup again. This article was prepared using Windows 7, but the steps are nearly identical for older versions of Windows/MCE.
Following is a screen by screen walk through using a Comcast DTA: