According to WikiPedia it's like a remote control with a laser for fluffs sake: At their core, laser tag systems typically use infrared signaling to track firing of the laser. In indoor play, a visible laser combined with theatrical fog typically provide the visual effect of firing, while having no actual role in transmitting the fire signal. In all but the most basic of systems, the infrared signal sent by the laser when it fires is encoded with information such as the identity of the pack from which it originated. This coding allows for scoring and may also act to discourage interference from unauthorized devices in the playing area