Interesting remote control on eBay.
Looks like you turn the wheel to select the function by controlling which hole is open to let the sound out.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2216905472&category=3638

Here it is together

Interesting is right, although the eronomics are a disaster and I can just see all the users and their sore thumb!

It appears that the dial would block or allow certain ultrasonic tones to select the function while the thumb button operated the striker mechanism.

Anthony

I had a Sony 15" color set that used one of those ultrasonic remotes. Everytime someone would rattle their car keys, it'd go crazy and change channels and make the volume go up and down. :rolleyes: