This is a NEC-SIRCS-JAPAN-RC5-SAMSUNG compatible, multiprotocol infrared remote control that replaces up to 6 existing remote controls into one. More protocols can be added later if needed.
http://www.techdesign.be/projects/011/011.htm
Designed for a model hovercraft, the controller consists of a Dual-tone multifrequency (DTMF) encoder based on the UM91214 Telephone dialler IC.
http://wiredworld.tripod.com/tronics/remote_control.html
This is a list of IR remote controller programming resources plus other online locations that offer help on programming various remote controls.
http://www.remotecentral.com/features/remotes.htm
http://www.web-ee.com/Schematics/Universal%20Remote/upr.htm
A radio controlled remote control, suitable for driving up to 3 loads using relays. With a 6 keys transmitter each relays is controlled indipendently. And you can also connect it to a PC!
http://www.nutchip.com/progetti/tre_canali_en.htm
http://www.rentron.com/Infrared_Remote_Control.htm
http://www.uoguelph.ca/~antoon/circ/src.htm
using ordinary AM radio receiver.
http://www.anatekcorp.com/ttg/tiptrick.htm#Testing remote control using ordinary AM radio receiver