No limit on any "type" of device. It controls 20 devices of any kind.

When you watch a DVD movie, you've got 3 devices operating - TV, DVD player, and receiver. If you program one of those 20 "devices" to control things when watching a movie, you can program any of the buttons to control functions for all 3 of the devices, without having to do a lot of switching from screen to screen.

Jack

"People generally quarrel because they cannot argue." - G. K. Chesterton