Prepayment metering system using encoded purchase cards

Abstract From the Canadian patent

A prepayment utility metering method and apparatus is described which uses encoded mag-stripe cards to transfer purchase information from the utility billing office to the customer's premises. The magstripe cards are read at the customer's premises by a microprocessor-controlled utility metering and control device which meters the utilities according to the amount purchased at the utility billing office. The value information encoded on the mag-stripe cards is comprised of the amount of the purchase coded in terms of number of shaft revolutions of the metering disk a, rate schedule for metering the value of the utilities consumed, and a special sequential password containing an encrypted …