FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
PROVISIONAL SPECIFICATION
(See section 10; rule 13)

1. Title of the invention. -

ELECTRONICALLY CALIBRATED SECURITY KEY FOR FUEL DISPENSERS

2. Applicant(s)
(a) NAME :
(b) NATIONALITY :
(c) ADDRESS :

LARSEN & TOUBRO LIMITED
An Indian company
L & T House, Ballard Estate, Mumbai 400 001, State of Maharashtra, India

3. PREAMBLE TO THE DESCRIPTION
The following specification describes the invention

TITLE OF THE INVENTION
Electronically calibrated security key for fuel dispensers
FIELD OF THE INVENTION
The present invention relates to a tamper proof fuel dispenser unit. More particularly, the invention relates to a device i.e. a calibrated key and method for providing multi-level security in fuel dispenser unit to prevent access for unauthorized calibration and tampering with the unit and enhance the overall security associated with the system.
BACHGROUND AND THE PRIOR ART
The process of calibration is a fixed amount of fuel being dispensed from the fuel dispenser, and the dispensed quantity of fuel is measured and entered through keypad to the system. If there is a difference in preset value and measured volume, multiplication factor commonly known as the K factor is changed.
It is known that key is metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated. Lock uses a set of obstructions, to prevent it from opening unless the correct key is inserted. The correct key has notches or slots corresponding to the obstructions in the lock, allowing it to rotate freely inside the lock So if proper shaped key is not inserted it's of no use. Physical structure of key it self will limit the chances of insertion of duplicate key. But if some one


manages to make a duplicate of key with the circuitry inside it, the serial number of key changes & pump will not accept such key.
The system is immune to the following common means of tampering
1. Removing power supply, shorting any wire to force the controller to enter calibration mode
2. To manually Edit the calibration factor stored in the memory (Since this device will not store any sensitive Data such as K-factor related to calibration process)
3. Making the duplicate key (The system has two fold security- only making duplicate key will not help in this case)
4. Making the duplicate key and also duplicating the circuit within, (since each 1-wire chip is unique in the world, no two chips will have same serial numbers.)
In the present scenario a jumper is provided on the encoder card which needs so as to short 10 pin of controller to ground to enter pump into the calibration mode. When the jumper is put on the given connector internally one of the I/O pin of microcontroller is pulled down & pump enters into calibration mode. Presently the encoder box assembly is sealed by wets & measure people. User has to cut the seal in front of wets & measure people to do the calibration of pump.
So presently there are two security levels


1. Physical seal
2. Password for software calibration menu on key pad.
But there are chances that someone will break the seal do the tampering & put some duplicate seal. So there is a need to ensure that even if seal is removed any other user should not be able to do the calibration.
The inventors have found that by unique design of calibration key and providing the same with unique identification code, security level of pump calibration can be enhanced which would prevent unauthorized access for calibrating the pump unit.
OBJECTS OF THE INVENTION
Accordingly, one object of the present invention is to provide multi-level security in fuel dispenser unit to prevent access for unauthorized calibration and tampering with the unit.
Another object of the present invention is to provide unique identification number to calibrated key.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the present invention relates to a tamper proof fuel dispensing unit enabled with a multi-level security to prevent unauthorized access to calibration and tampering of the system. The purpose of the invention is to provide enhanced levels of security so


as to prevent unauthorized use and calibration of dispensing units.
In the present invention a specially designed lock and key mechanism is installed on sites. The uniqueness of the key lies in its programmed LASER ROM 64-bit serial number. This serial number of the IC is unique in a way that duplication of the key will not default the system providing a communication link between the IC embedded into the key head and controller based on 1-wire protocol. The IC used in the invention is DS2411R (SOT23 pack).
Accordingly the system as described in the present invention is programmed in such a way that only after detecting the key it will allow pump to enter into calibration mode.
The DS2411 silicon (semiconductor chip) serial number is a low cost, electronic registration number with external power supply. It provides an absolutely unique identity that can be determined with a minimal electronic interface. The DS2411's registration number is a factory-laser ROM, 64 -bit that includes a unique 48-bit serial number, an 8-bit CRC, and an 8-bit family code (Olh). Data is transferred serially through the semiconductor's 1-wire chip. The external power supply is required, extending the operating voltage range of the device below typical 1-wire devices.


General working:
According to the present invention the DS2411's registration number is accessed through a single data line. The 48-bit serial number, 8-bit family code, and 8-bit CRC are retrieved using the 1-wire protocol. The protocol defines the bus transactions in terms of the bus state during specified time slots that are bus-master-generated falling edges on the I/O pin. All data is read and written least significant bit first. The device requires a delay VCC power-up and initial 1-wire communication, tPWRP (1200_s). During this delay time the device generates presence detect pulses.
The 1-wire bus has a single bus master and one or more slaves. In all instances, the DS2411 is a slave device. The bus master is typically either a microcontroller or a semiconductor bridge chip such as the DS2480, DS2490 or DS 1481.
The 1-wire bus has a single data line, I/O. it is necessary that each bus is able to drive I/O at the appropriate time. This criteria is facilitated by means of each device having an open drain or three state output. The bus master can have the same equivalent circuit. If a bi-directional pin is not available on the master, separate output and input pins can be connected together. The 1-wire bus has a maximum data rate of 15.4 kbps in standard speed and 125 kbps in overdrive.


With the implementation of the technique, a multi level
security for fuel dispenser unit is provided such that-
(i) physical seal
(ii) password for software calibration menu on
keypad
(iii) calibration key structure
(iv) unique identification number of key.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1 illustrates a structural view of the calibration key
Figure 2 illustrates a block diagram of the calibration key.
Figure 3 illustrates flow diagram for secure calibration key program.
Figure 4 illustrates a schematic view of the secured calibration key of the present invention.
DETAILED DESCRIPTION OF THE ACCOMPANYING FIGURES
Figures 1,2 and 4 show a structural view of calibration key (1) of the present invention. It comprises secured communication line (2), ground (3) and earth (4) connected to silicon chip (5). Inside the secure calibration key (1) a tiny Silicon Serial Number chip (DS2411R in this case) is embedded. The chip requires


no external power supply to work. Specialty of this DS2411 is that it has an embedded unique 64 bit serial number. When the pumps are delivered to sites, this serial number is stored in a secured memory inside controller. When key is entered for a particular meter into system circuit gets completed. Controller will initially validate the serial number of key if key is correct one then only calibration related menu will be displayed on keypad.
Figure 3 shows the flow chart for secured calibration ket program. Initially calibration password is entered so as to enter into calibration menu from keypad. After initiation of calibration menu controller starts polling for key address. That means it will continuously check whether key is present or not. Then the key is required to be inserted into the lock provided. When controller finds key, it reads the serial number of the key. If this number matches with the serial number stored into the database then only it will allow entering into calibration mode.