All signals are means of visually communicating a message.
The source of the message is the official who gives the signal. The destination of the message may be, in different cases, other officials, players, coaches or spectators. Visual signals may have to be used where either distance or noise prevent audible signals from being heard, or where an audible signal is inappropriate. Signals Sup11 and Sup12 are intended primarily for communication between the Referee and the on-field timekeeper. Signals Sup16 to Sup19 are intended for kick out of bounds situations.