My Nomad is installed and working with two DVRs, but does not see the third DVR (the one I bought it for). All three DVRs have the same settings for sharing and allowing external devices and I have tried restarting the third DVR & the Nomad twice without any luck. The Nomad web page indicated it works with HD DVR (model HR20 or later) so I ordered one. The manual lists models R22, HR20, HR21, HR22, HR23 and HR24 and "additional models may be added in the future." The problem DVR is a HR21P-200. Should this DVR work with the Nomad or is it one that may be added "in the future"?