It can only be played back on the dish equipment it was tied to.
Wanted to throw a clarification here, because I used to think the same thing. I recently had a 622 fail (hdmi port) and happened to have a backup 622 that I owned. I was able use an EHD to store my content from rece1ver 1 and restore it or play it from receiver 2. Still had to manually program all my events though.
CSR said receivers of the same model # can play the content from an EHD.