The infra red remote control unit is a common component of many audio visual consumer goods such as televisions, VCR's and Hi-Fi's.
The system consists of two components. A hand held transmitter and a receiver located in the appliance. On pressing a button on the transmitter a unique code is generated by encoder micro chips. This code is converted into a stream of infra red pulses and sent from the front of the transmitter. The receiver picks up the infra red signals and decodes the embedded pulses. If it recognises the pulses it will act accordingly, if not they will be ignored.
In the last few years there have emerged `learning' or `universal' infra red remote controls. These have the ability to `look at' any stream of infra red pulses and store them in memory. These stored pulses can the be replayed and the receiver cannot tell the difference from the original handset's transmissions.
