E:
Looking at the picture is says the signal goes from 4.5 volts to ground so it looks like its an analog signal.
I would use a palmpad hack myself and a magnetic contact switch myself! That way you could get the X-10 signal into your MR26a without using an SECU16 input. The nine volt mod would also run for a pretty long time.
I'm going to try to repost that How-to (Hack A PalmPad) this week since the pics got lost in the crash. I also need to use this for a car monitor that I want to work on.
My time this week has been chewed up with family matters, but hopefully I can get on this soon. I ordered some 555 timers, binary counter chips, and various other items (resistors, capacitors, relays, etc...) from Jameco and they came in today. I have a very rough schematic that I wouldn't mind sending to people to review on how I'm going to do this (smee are you interested?!?!), but don't want to post anything till I get it working.
Regards,
BSR