A system of controlling access to commercial fueling dispensers, such as those used at trucking companies and taxi companies.

At retail motor fuel sites open to the public, it is generally required that an attendant be on duty to operate the pumps and collect the money. But at commercial fueling sites, drivers who are authorized to obtain fuel at the location are given coded cards or keys that operate the pumps. These facilities are referred to as cardlock or keylock locations. Both operate on essentially the same principle.

When a driver arrives at a keylock location for a fill-up, he inserts a key in the pump. The pump "reads" the key and determines that the key owner is eligible to obtain fuel at that location. The pump is also able, through the key, to identify the vehicle being fueled.

Not only do the coded keys provide security for commercial fueling sites, but they also make it possible for the owner of the site to elicit detailed records on each transaction: identity of driver, identity of vehicle, number of gallons dispensed-even the approximate mileage on the vehicle.