Pushing a button on a remote control sets in motion a series of events that causes the controlled device to carry out a command. The process works something like this:

You push the "volume up" button on your remote control, causing it to touch the contact beneath it and complete the "volume up" circuit on the circuit board. The integrated circuit detects this.The integrated circuit sends the binary "volume up" command to the LED at the front of the remote.The LED sends out a series of light pulses that corresponds to the binary "volume up" command.