Transponders

The system operates by matching the signal from a transponder on a laptop computer to a transponder on the person who is authorised to move that computer past the checkpoint. The transponders for the people are credit card sized and can be carried in a pocket or out of sight. Due to their low power characteristics, they can be read up to 13 meters away from the reader. The transponders are passive (do not have a battery) and have a lifetime of more than ten years