Just an FYI for other owners who may be having remote issues.
As soon as we purchased the DCX-3400-M boxes, we started having an issue where all remotes would become unresponsive at the same time. Certain functions would work, but significant delay, unable to 'change' channel, etc. Outside of this 'odd glitch', they worked like a charm.
Anyway, long story short -- a very techy friend was over and I picked his brain -- issue was our Roomba virtual walls and the HDPVR remote IR sensors (so I re-scheduled Roomba run-times outside of TV time ). With the popularity of the Roomba product, I just wanted to mention it in hopes it may help someone else who may be having the same frustrations.