I have Cox digital cable with Motorola DCH3416 hooked up in the living room. I subscribe to HBO and Showtime and the broadcast is great.

Cox sent me another DCH3416 and I hooked it up in the bedroom. However, the second unit does not show HBO or Showtime. I get a "call COX to subscribe" screen.

Is there a way to activate HBO and Showtime on the second unit?

Why don't you call Cox and say you can't get those channels on that box. Maybe rebooting the box might help by unplugging and plugging back in.

You will have to call customer service and have them activate the second DVR. Each DVR is registered separately in the system...