GB2236422A - Pre-payment token for supply of a commodity - Google Patents

Abstract

In a card prepayment system. e.g. for the supply of electricity, gas or water to a consumer, the cards (1) carry data representing credit at a first location (3) on the card in a relatively low density format and further data at a second location (5) in a relatively high density format. The consumer's metering equipment (7) is able to read data only at the first location. thus enabling a relatively inexpensive card reading device to be used in the consumer's equipment. The data at the second location typically comprises consumer identification data which is read by the supply authorities dispenser equipment (9) when further credit is purchased. Metering equipment (7) wipes location clear of data or otherwise corrupts the data after allowing the use of the commodity up to the value of the credit. Location (3) may have 10 bits per centimetre while location (5) has 30 bits per centimetre. Dispenser equipment (9) provides an erase code for security purposes which differs from the erase code at the first location. <IMAGE>

Description

Prepayment systems for supply of a commodity This invention relates to prepayment systems for supply of a commodity, e.g. water, electricity or gas.

In the past such systems have been operated by insertion of coins into a consumer's metering equipment which cause the equipment to allow consumption of a quantity of the commodity corresponding to the value of the coins inserted.

More recently, systems have been developed which are operated by the presentation to a consumer's metering equipment of a token, e.g. a card or key, carrying encoded data representing credit which the consumer has previously purchased, which data the metering equipment reads to determine the value of the credit, and hence the quantity of the commodity which the consumer is to be allowed to consume. Such a system is hereafter referred to as a prepayment system of the kind specified.

In a prepayment system of the kind specified it is frequently required that the token should carry information additional to the credit value, for example, data identifying a particular consumer as the token user, or identifying a particular metering equipment with which the card is intended to be used. Such a requirement raises the required data density on the token to a level such that the equipment for reading the data on the token needs to be of a relatively sophisticated nature e.g. of the kind using a motorised transport mechanism to move the token past a read head rather than manual movement of the token past a read head.

Consequently the cost of the consumer metering equipment is increased.

It Is an object of the present invention to provide a prepayment system of the kind specified wherein this problem is overcome.

According to the present invention in a prepayment system of the kind specified the tokens each carry at least said data representing credit at a first location on the token in a relatively low density format, and further data at a second location on the token in a relatively high density format, and the consumer's metering equipment is arranged to read data at said first location only.

In a system according to the invention the data carried at said first location may also include data identifying some of the consumer's metering equipments of the system for use in preventing use of the token with other consumer's metering equipments of the system.

The data carried at said second location is normally arranged to be read by dispenser equipment means arranged to enter data representing credit at said first location on purchase of credit by a consumer.

Normally said data carried at said second location uniquely identifies a particular consumer in the system.

The data carried at said second location preferably also includes at least some of the data carried at said first location.

One prepayment system in accordance with the invention for controlling the supply of electricity to consumers will now be described by way of example with reference to the accompanying drawing which is a diagram illustrating the system.

Referring to the drawing, the system makes use of tokens in the form of cards of a plastics material 1 each of which has on one main face two parallel strips 3 and 5 of magnetic material, each strip being adapted to store binary coded digital data in the form of variations in the magnetic state of the magnetic material along the length of the strip.

The system further includes a metering equipment 7 for each consumer, and a number of dispenser equipments 9. The metering equipments, of course, are each located in, or closely adjacent, a respective consumer's dwelling or other premises wherein an electrical load to be supplied with electricity is located. The dispenser equipments are located in premises accessible to consumers, such as offices or shops owned by the electricity supply authority.

In operation of the system credit is purchased by a consumer by presenting a card 1 to a dispenser equipment 9, as further described below.

After such purchase twenty data bits are stored on the strip 3 in low density format e.g. 10 bits per centimetre, and forty-four data bits are stored on the strip 5 in relatively high density format, e.g. 30 bits per centimetre.

The low density format data comprises all the data required to be transferred from a card 1 to a consumer's metering equipment 7 in operation of the system. To this end the low density data includes four bits which identify the electrical energy value of the credit purchased by the consumer. Suitably two of these four bits represent one of a small number of electrical energy units e.g.

1, 2 or 5 units and the other two bits represent one of several multipliers e.g. 1, 10, 100 or 1000. A further ten data bits comprise a so-called meter code which identifies the consumer's metering equipment 7 with which the card 1 is intended to be used, although not uniquely, as further explained below. A further pair of data bits comprise an erase code used as further explained below, and the remaining four bits comprise a control code available for providing further instructions to consumer's metering equipment, e.g.

tariff change information, as required.

The high density format data comprises all the data stored in low density format on the strip 3 plus a further twenty-four data bits which uniquely identify the customer to whom the card 1 has been issued.

To use the electricity represented by the credit data on a card 1, the consumer manually moves the card 1 past a read head in the appropriate consumer's metering equipment 7, the head being arranged to read the data on the strip 3 only of the card 1. If the meter code and erase code data as read are satisfactory, as further explained below, the metering equipment 7 registers credit to the value represented by the credit data on the card 1. The metering equipment 7 then allows use of electricity up to the value of the credit. To this end the metering equipment 7 includes a contactor connected between the electricity supply and the customer's load and a metering unit which measures the amount of electrical energy used in the load and reduces the credit accordingly until no credit remains, whereupon the contactor is opened.

Having read the data on the strip 3, the metering equipment wipes the strip 3 clean of data or otherwise corrupts the data on this strip 3.

For credit to be registered, the erase code is required to be different from the erase code when the preceding registration of credit took place. This provides some security against re-use'of a card on failure of the metering equipment 7 to destroy properly the data on the strip 3 on credit registration.

The meter code on the card has to correspond, or bear a predetermined relation to a code stored in the metering equipment for credit to be registered. Whilst the number of bits in the meter code is insufficient to uniquely identify each metering equipment (twenty-four bits being required to uniquely identify each customer), the meter code renders each card 1 capable' of operation only with a very small fraction of the total number of metering equipments 7 in the system, thus reducing the possibility of illicit trade in cards capable of registering credit.

To obtain further credit the consumer presents the card 1 to a dispenser equipment 9. The dispenser equipments 9 each incorporate a motorised card transport system which passes the strips 3 and 5 past read and record heads in the dispenser equipment 9. The read head reads the data on the strip 5 to establish the consumer's identity and the data previously written on the strip 3 of the card 1. The dispenser equipment 9 then records appropriate new data on the strip 3 in accordance with further credit purchased by the consumer, e.g. by inserting coins into the dispenser equipment 9, and the requirement for the erase code to differ from the erase code read off the card 1.

The presence of data on each card 1 uniquely identifying the consumer to whom the card has been issued and reading of this data by the dispenser equipments 9 enables each credit purchase transaction to be recorded by the supply authority against the name of the relevant consumer, the dispenser equipments 9 being connected with a computer system for this purpose. By comparing the credit purchased by each consumer against the energy use as recorded by the consumer's metering equipment 7, a check on possible fraudulent use of electricity can be made.

It will be appreciated that the dispenser equipments 9 may suitably be arranged to enter customer identification and meter code data on a card 1 when a card 1 is first issued to a consumer.

It will be understood that in other systems according to the invention the data recorded on the tokens may differ from that described above by way of example. However, in essence the invention requires that the token has two data storage locations in which the data storage densities are different, and that all data required to be transferred to a metering equipment, which data necessarily includes purchased credit value, are stored in the lower data density location.

It will further be understood that whilst in the system described above the two locations are on different parallel strips of magnetic material, in other systems the locations may be different tracks on one and the same strip.

It will be further understood that in other systems in accordance with the invention other than magnetic data storage may be used. For example, optical data storage may be used.

Claims (11)

1. A prepayment system of the kind specified wherein the tokens each carry at least said data representing credit at a first location on the token in a relatively low density format, and further data at a second location on the token in a relatively high density format, and the consumer's metering equipment is arranged to read data at said first location only.

2. A system according to Claim 1 wherein the data carried at said first location also include data identifying some of the consumer's metering equipments of the system for use in preventing use of the token with other consumer's metering equipments of the system.

3. A system according to Claim 1 or Claim 2 wherein the data carried at said second location is arranged to be read by dispenser equipment means arranged to enter data representing credit at said first location on purchase of credit by a consumer.

4. A system according to any one of the preceding claims wherein said data carried at said second location uniquely identifies a particular consumer in the system.

5. A system according to any one of the preceding claims wherein said data carried at said second location also includes at least some of the data carried at said first location.

6. A system according to any one of the preceding claims wherein said data is carried on said tokens in the form of variations in the'magnetic state of a magnetic material along a length of said material.

7. A system according to Claim 6 wherein each said location is on a separate strip of said material.

8. A system according to Claim 6 wherein said locations are different tracks on one and the same strip of magnetic material.

9. A system according to any one of the preceding claims wherein said commodity is electricity, gas or water.

10. A prepayment system for supply of a commodity substantially as hereinbefore described with reference to the accompanying drawing.

11. A token suitable for use in a prepayment system according to any one of the preceding claims.