Ever wondered what a remote control signal actually looks like? Well, it's a beam of infrared light that flashes rapidly kinda like morse code, the actual message is carried in the way the light flashes, not the IR frequency as many might expect.
Most signals create the message by varying the amount of time the light is OFF between the flashes, although some (like Sony) vary the ON time to create the message, and a few vary both but don't worry about that now.