http://www.beautifulwood.net/dcremote.html
This is from Dennis Peacock's site and I followed it to the letter. This stuff is pretty simple once you get one in your hands.
Guess what? Now I'm replacing the two 24-hour mechanical timers that control my pool pumps with, get this, SPRINKLER timers! Yep, they put out a 24 V signal and I picked up two contactors that have a 24 V coil (input) and can handle the 240 V the two pumps require. Now I can run my pool pumps every other day instead of every day.