A transmitter in the back of an electronic scoring vest can send a signal to a scoreboard.
Olympic taekwondo will use wireless scoring

A transmitter in the back of an electronic scoring vest can send a signal to a scoreboard.
Medals are awarded in four different weight classes for men and women, putting eight medals up for grabs in London. A country can only send competitors for two weight classes per gender.
There’s never been a woman to compete in her discipline, so she competed with men, and broke their bones.
This year, Taekwondo athletes will wear socks and clothing fitted with electronic sensors made by Spanish company Daedo.