Paramount to the realisation of this system is the interaction it holds with the main referee. A prototype watch
has been developed that houses all the necessary components to allow the system to work during real match
situations. This watch features an LCD display, lithium polymer battery, Xbee wireless transceiver and two
buttons. When the referee observes a forward pass played, he/she presses the button corresponding to the passing
team. At this point the wireless transceiver relays the signal to the ‘base station’ for the algorithm to begin. If any
players are in an offside position their jersey numbers are sent back to the watch to be displayed on the LCD. It is
then up to the referee to determine if the specified players are actively involved in play. The referee then signals
for an offside infringement if this is the case.