This is a very useful tool. In the eye or the hands (typically the hands) or some other moveable place of the body, a computer with a radio, cellular phone, etc. is inserted. When the person makes a gesture (shall we say tapping the fingers or moving the hand), the computer interprets the muscle signals and converts it into a code. There are three methods it does this. The first method is the simplest: the person memorizes the code. The second involves the person thinking the code and doing a arbitrary hand gesture or tapping to get the point across. The third involves pre-programming a code and having the computer take over the body to do the code. This means the person can sit back while it seems like they are randomly drumming the fingers. Other methods of transfer include boot tapping, eye movements, lip movements, head and neck movements, handshake pressure points (so a press in the correct direction means A, another push B, etc.), and other, similar methods. It also includes the decoder for someone else's radio.