Some 2,440 Chinese students taking a national exam have been caught using high-tech cheating gear that wouldn't be out of place in a spy film. According to state media, invigilators detected abnormal radio signals that were being used to transmit the answers in code to candidates, who wore wireless ear pieces or placed "electronic erasers" on their desks.The organizers of the scam sent fake candidates to take the test, who quickly left after memorizing the questions. They then broadcast the correct answers to candidates, who had paid $330 for the service.