InfraRed LEDs in remote controls

[EduardoG]

Does anyone know how the InfraRed LEDs in remote controls (for devices such as TVs) work! I mean what do they vary for the TV to know what to do according to each button? Is it a different wavelength? If so, how would I go about doing this in a circuit, please be as specific as possible, this is quite important!

[Sensei]

The LED is transmitting a square wave. If you were to hook an o'scope to the LED, you would see the wave. Usually, an IC takes care of the encoding based on which button is pressed. At the receiving end, an amplifier picks up the signal and sends it to another IC which decodes the signal. Basically, all the LED is doing is transmitting a square wave in place of a wire. That's the easy part...the more complex part is encoding and decoding of the data that is being sent. For that, you're better off picking up a book and researching it.

[EduardoG]

Don't suppose you've got any ideas where I should look for this information have you? How do they determine which button's pressed is it the speed of the pulses or number of pulses and how would I go about changing this in an IC?