The HR21 has two RJ45 jacks. One is used for getting On Demand or Media Share via ethernet and the other can be used to daisy-chain another ethernet device (Xbox 360, etc.) The HR20-100 also has two RJ45 jacks but I don't know if the second one is functional.
Thank you, mine new one has2 RJ45 jacks. Now I know what they are for. I do have a question though. I can access my computer through the ethernet on the receiver box, can DTV do the same? And my movies are all AVI format, on my hard drive on my computer. What format do I need to watch them through the HR21 box. Do they have to be windows files. Any help on this ?
Check out TVersity » Home and you can have your HR20 get stuff streamed from your computer. It will convert it to the appropriate format. I don't know if the HR21 has the same ability, but I would assume that it does. As I said the HR20 definitely can do it. If you like streaming stuff that is not in a windows media format (Flash, xVid, OGM, etc) then Tversity is a great program to use.
It doesn't have to be Windows, but I don't know of any non-Windows applications which transcode as many formats as Tversity. The HR20/21 only recognizes MPEG2 video, not avi (there are programs which will convert the files, however).
Twonky will work with Windows, OS X or Linux (an add-on is needed to transcode MP3 audio files to LPCM).