Long checkout lines at the grocery store are one of the biggest complaints about the shopping experience. This is mainly due to the time consuming use of UPC barcodes. These codes act as product fingerprints made of machine-readable parallel bars that store binary data.
Created in 1970s to speed up the checkout process, barcodes have certain disadvantages:
It is a read-only technology, which means it cannot send information.
It can easily be forged.
Barcode scanning is time consuming.
To overcome these, the barcodes are being replaced by smart labels, also called radiofrequency identification tags.
RFID tags are intelligent barcodes that can literally talk to a networked system to track every product that is bought.
The automotive industry also makes use of RFID batteryless transponders that offer a high level of security at low cost. The theft of vehicles with electronic immobilizers decreased to about one-tenth compared to those without immobilizers. This is based on the RFID technology.
RFID is a technology that uses radio signals for automatic identification by transmitting data in a machine-readable form using radiofrequency as the carrier medium.
This paper gives an in-depth knowledge about RFID technology and its applications
Almost every product in the market has a barcode printed on it. Barcodes are machine-readable parallel bars that store binary information, revealing information about the product. Thus, it acts as the product fingerprint. As we go to the supermarket to buy things, the checkout person runs our selection over the scanner to scan the barcode, thereâ„¢s an audible beep, and we are told how much money we owe.
But the days of barcode are numbered. The reason is that a technology called radiofrequency identification (RFID) is catching on.RFID tags are being used by corporations to track people and products in just about every industry. They transform everyday objects like cargo containers, car keys, and even clothes on the rack at a shopping mall into mini nodes on a network. Databases then record the location and status of these network nodes to determine product movements. , 
This technology can completely replace barcodes.
The automotive industry makes use of small RFID tags that offer a high level of security at low cost.
A lot of developments are taking place in RFID technology that will change the course of the industry, particularly in the supply chain area.
A tag is any device or label that identifies the host to which it is attached. It typically does not hinder the operation of the host or adversely affect its appearance.
The word transponder is derived from the words transmitter and responder. The tag responds to a transmitted or communicated request for the data it carries.
The transponder memory may comprise of read-only (ROM), random access (RAM), and non-volatile programmable memory for data storage depending on the type and sophistication of the device. The ROM-based memory is used to accommodate security data and the transponder operating system instructions which in conjunction with the processor or processing logic deals with the internal Ëœhouse-keepingâ„¢ functions like response delay timing, data flow control and supply switching. The RAM-based memory is used for temporary data storage during transponder interrogation and response. The non-volatile programmable memory may be of several types of which the electrically erasable programmable read-only memory (EEPROM) is the most common. It is used to store the transponder data and needs to be non-volatile to ensure that the data is retained when the device is in its quiescent or power-saving Ëœsleepâ„¢ state.
Data buffers are further components of memory used to temporarily hold the incoming data following demodulation and outgoing data for modulation and interface with the transponder antenna. The interface circuitry provides the facility to direct and accommodate the interrogation field energy for powering purposes in passive transponders and triggering of the transponder response. The transponder antenna senses the interrogating field and serves as the means for transmitting the transponder response for interrogation.
CLASSIFICATION OF TAGS
On the basis of the presence of battery, tags can be classified into active or passive tags.
Active tags are powered by an internal battery and are generally read/write devices. They contain a cell having a high power to weight ratio and are capable of operating over a temperature range of -50 to +70 degree Celsius. Active tags have a finite life time. A suitable cell coupled to suitable low power circuitry can ensure functionality of ten or more years depending on operating temperatures, read/write cycles and usage. They have greater size and increased cost compared to passive tags.
Passive tags operate without an internal battery source, deriving the power to operate from the field generated by the reader. They are hence lighter than active tags and have greater life time. They have shorter read ranges compared to active tags. They are also constrained in their ability to store data and perform well in electromagnetically noisy environments.
RFID tags can also be classified on the basis of coupling into inductively and capacitively coupled tags.
Inductively coupled RFID tags consist of the silicon microprocessor which vary in size depending on their purpose and metal coil which is made of copper or aluminum wire that is wound into a circular pattern on the transponder. This coil acts as the tagâ„¢s antenna. The tag transmits signal to the reader with the read distance determined by the size of the coil antenna. It also consists of an encapsulating material of glass or polymer that wraps around the chip and coil. Inductively coupled RFID tags are powered by the magnetic field generated by the reader .The tagâ„¢s antenna picks up the magnetic energy and the tag communicates with the reader. The tag then modulates the magnetic field in order to retrieve and transmit data back to the reader. Data which is transmitted back to the reader is directed to the host computer. These tags are expensive due to the silicon, the coil antenna and the process that is needed to wind the coil around the surface of the tag.
Capacitively coupled RFID tags consist of an RFID chip and an antenna made from two plate electrodes. The reading mechanism between the tag and the reader is through capacitive coupling. Placing the tag in an electric field powers the tag. The field gradient across the tag results in a charge buildup between the plates and hence a potential difference which is used to energize the small silicon IC at its center.,
Data stored in data carriers require some organization and additions like data identifiers and error detection bits to satisfy recovery needs. This is known as source encoding. Standard numbering systems such as UCC/EAN can be applied to data stored in tags. Tags are basically used to carry
1.identifiers, in which a numeric or alphanumeric string is stored for identification purposes or as an access key to data stored in a computer or information management system.
2. Portable data files in which information is organized for communication. Tags can be obtained that can store single bits to kilobits. The single bit devices are used for surveillance purposes. Retail electronic article surveillance (EAS) is the typical application which activates an alarm in the interrogating field. They can also be used for counting applications.
Devices characterized by data storage capacities upto 128 bits are sufficient to hold a serial or identification number together with parity check bits. These devices may be manufacturer or user programmable. Tags with data storage capacities upto 512 bits are user programmable and suitable for accommodating identification and other specific data like serial numbers, package content, key process instructions and results of earlier interrogation/response transactions. Tags with storage capabilities of 64 kilobits are carriers of portable data files. By increasing the capacity, facility can be provided for organizing data into fields or pages that may be selectively interrogated during the reading purpose. Data transfer rates are linked to carrier frequency. The higher the frequency, the higher the transfer rates. Depending on the memory, the tag contains data that can be read-only; write once read many (WORM) or read /write. Read-only tags are low capacity devices programmed at source usually with an identification number. WORM devices are user programmable devices. Read/write devices are also user programmable but allow the user to change data stored in a tag. Portable programmers may also be present that allows in-field programming of the tag while attached to the item being identified or accompanied.
The reader/interrogators can differ considerably in complexity depending on the type of tags being supported and functions to be fulfilled. The overall function is to provide the means of communicating with the tag and facilitating data transfer. Functions performed by readers include signal conditioning, parity error checking and correction. Once the signal from a transponder has been correctly received and decoded, algorithms can be applied to decide whether the signal is a repeat transmission and may then instruct the transponder to stop transmitting. This is known as Command Response Protocol and is used to circumvent the problem of reading multiple tags in a short span of time. Using interrogators in this way is also referred to as Hands Down Polling. A more secure, but slower tag polling technique is called Hands Up Polling which involves the interrogator looking for tags with specific identities and interrogating them, in turn. A further approach uses multiple readers, multiplexed into one interrogator but results in cost increase.
RANGE AND POWER LEVELS
The range that can be achieved in an RFID is determined by:
1. The power available at the reader/interrogator to communicate with the tags.
2. The power available within the tag to respond.
3. The environmental conditions and structures, the former being more significant at higher frequencies including the signal to noise ratio.
Although the level of available power is the primary determinant of range, the manner and efficiency in which that power is deployed also influences the range. The field or wave generated from an antenna extends into space surrounding it and its strength diminishes with respect to distance. The antenna design determines the shape of the field or propagating wave delivered so that range is also influenced by the angle subtended between the tag and antenna.
In the space free of any obstruction or absorption mechanism, the strength of field reduces in inverse proportion to the square of the distance. For a wave propagating through a region in which reflections can arise from the ground and from obstacles, the reduction in strength can vary as an inverse fourth power of the distance. Where different paths arise in this way, the phenomenon is called multi-path attenuation. At higher frequencies, moisture presence can cause absorption which can further affect the range. Where a number of reflective obstacles are to be encountered within the applications under consideration, which may vary from time to time, it may also be necessary to establish the implications of such changes through an appropriate environmental evaluation.
The power within the tag is generally much less than that from the reader, requiring sensitive detection capability within the reader to handle the return signals. In some systems, the reader constitutes a receiver and is separate from the interrogation source or transmitter, particularly if the up-link (from transmitter to tag) carrier is different from the down-link (from tag to reader).
100-500mW power are values quoted for RFID systems, whereas the actual values should be confirmed with the appropriate regulatory authorities in the countries where the technology is being applied. The form in which the power is delivered, pulsed or continuous, and the associated values are also indicated by the authority.
An RFID system consists of RFID tags ,a means of reading or interrogating the tags and a means of communicating the data to a host computer or information management system. The system will also include a facility for entering or programming data into tags, if it is not done at the source by the manufacturer. There may also be present antennas for communication between the ag and the reader.
The reader sends out a radio frequency wave to the tag and the tag broadcasts back its stored data to the reader. The system has two antennas, one for the tag and the other on the reader. The data collected from the tag can either be sent directly to a host computer through standard interfaces or it can be stored in a portable reader and later updated to the computer for data processing. The automatic reading and direct use of tag data is called Ëœautomatic data captureâ„¢.
When the tag which is battery free,is to be read ,the reader sends out a power pulse to the antenna lasting for about 50ms.The magnetic field generated is collected by the antenna in the transponder that is tuned to the same frequency. This received energy is rectified and stored on a capacitor within the transponder. When the power pulse has finished, the transponder immediately transmits back its data, using the energy stored within its capacitor as its power source. The data is picked up by the receiving antenna and decoded by the reader unit. Once all the data has been transmitted, the storage capacitor is discharged resetting the transponder to make it ready for the next read cycle. The period between transmission pulses is called sync time and lasts between 20ms and 50ms depending on the system set up.
The transmission technique between the transponder and the reader is FSK.This approach has good resistance to noise and is cost effective to implement.
Reading distance: The actual reading distance depends on the transponder type, electromagnetic noise, transponder orientation, antenna type. In general, a 32mm glass transponder can be read with a stationary reader and gate antenna from a distance of about 1m.Larger transponders can achieve ranges upto 2m with handheld readers offering lower ranges upto 250mm.
Data accuracy: A 16-bit cyclic redundancy check algorithm is used to ensure that only valid data is sent from the reader to its associated controller.
Antenna selection: Of the antenna types, the one giving larger read ranges is selected. Electromagnetic noise affects the readout pattern.
Transponder orientation: For maximum range, the antenna orientation with respect to the transponder must be optimized for maximum coupling. The orientation in line with a ferrite antenna produces the largest read ranges from 2mm glass transponder.
Reading speed: Many applications require that that transponder must remain in the reading range. Since a standard stationary reader completes one cycle in abut 120ms, transponders must remain in the boundaries of a readout pattern for at least that amount of time.
Immobilizers are the security systems in automobiles. The latest generation of RFID transponders called crypto transponders can be used as the chief part of immobilizers.
Key-based immobilizer systems consist of four main components. The core of the system is the transponder, a batteryless device which is available in various form factors and with different functionalities. For operation, the transponder has to be supplied with energy from an external source. The transceiver generates a high frequency magnetic field which is radiated by an antenna coil. The energy activates the transponder and it sends a data stream in form of a modulated RF signal. This signal is demodulated by the transceiver and then passed to the controller for data processing. Different physical principles for RFID systems have been established on the market. Concerning the transmission of energy, two different systems can be distinguished.
Full Duplex Systems. The energy for the transponder and the data signal generated by the transponder are transmitted at the same time.
Half Duplex Systems. The transmission of the energy for the transponder and the data signal from the transponder are done consecutively. The transponder stores energy in a capacitor and as soon as the transmitter is switched off, the energy is used to transmit data. The different techniques have an impact on system design and reading range, but have no impact on the system.
From the cryptographic point of view, the problem of immobilization consists of two different tasks, the identification of the driver and proving his identity, the authentication. Several cryptographic means are applicable for driver authentication.
The authentication is based on the knowledge of a secret, for example a password or PIN (Personal Identification Number) that has to be presented to proof the identity. For automotive applications any method using a keyboard is unacceptable for most of the users. In addition the level of security is unacceptable.
Biological attributes, such as fingerprints, voice, retinal or face patterns could theoretically be used for authentication of the driver. However, the technical effort for such systems is still high compared to key-based immobilizers and not acceptable for automotive applications. In addition, the problem of renting a car to someone else and emergency use of a vehicle becomes a critical issue.
Authentication by means of possession is the most common method and will also be widely spread in future. The simplest implementation is the possession of a mechanical key. A much higher security is offered if the key contains an electronic tag such as a transponder. To start the vehicle, the mechanical key and the code in the transponder must match.
All cryptographic systems described above are based on static authentication procedures, that means the security system of the car can verify the identity of the key but the electronics in the key cannot check the identity of the communication partner. A mutual authentication procedure which also allows the key to verify the identity of the communication partner is one feature that would improve the security level of the system.
A much higher level of security can be achieved with a simple symmetrical algorithm known as challenge / response protocol. The security system of the vehicle can check the identity of the key by sending a question (a challenge) and verifying the answer (response). The correct answer can only be given if a secret is known that is shared by both partners. This challenge/response
concept has several advantages. During normal use, the secret is not exchanged and both challenge and response vary from cycle to cycle.
Standard Security Architectures using RFID
Various security systems using RFID transponders have been established on the market.
Fixed Code Systems are the most commonly used. During initialization, the controller learns different identification codes stored in the transponders that belong to a vehicle. When the driver places the ignition key in the lock cylinder, the fixed code in the transponder is read and compared to the codes stored in the memory of the controller.
The level of security depends to a great extend on the type of transponder used. There are write once transponders on the market which are delivered unprogrammed. Programming is done by the user. Commercially available readers/writers allow to pick up the code in the transponder while away from the vehicle and to program an unprogrammed unit. Thus a copy of the fixed code has been generated which cannot be distinguished from the original. True Read Only systems on the market are factory programmed with a unique identification number. These systems do not allow copies. However, it is possible to emulate the data signal on the radio frequency level. The effort to design an emulator is considerable and requires RF design knowledge.
Rolling Code Systems operate in the same way as fixed code systems except that the secret code in the key is only valid for a certain period of time, typically from one ignition cycle to the other. The System Security Controller reprograms the transponder (which is a Read/Write type) periodically. The secret is changed, but in terms of cryptographics the procedure is still a static authentication. To guarantee the reliability of the system, resynchronization procedures have to be implemented in case the transponder programming fails or the transponder is reprogrammed by mistake while away from the vehicle. Especially these procedures for resynchronization are the most critical issues in such systems.
A simple mutual authentication can be provided by password protected transponders. The transponder will deny access to the secret data information stored in its memory unless a password is presented and thus the identity of the reader proven. The length of the password can vary depending on the required security level. The password is usually transmitted in plain text and can be picked up or guessed if the transponder is available. Depending on the length of the password, the time to guess the password can vary from several minutes to several years. A limitation of the system is the total transaction time which can be unacceptable for practical use in the application.
Combined Rolling Code / Password Systems can also be implemented using password protected Secured Read Write Transponders. They provide a higher level of security.
Crypto Transponders are the second generation of transponders for use in immobilizers. The new generation of crypto transponders developed by Texas Instruments are based upon the TIRIS TM half duplex RFID technology and are compatible to all standard RF interfaces of the TIRIS TM product range.
The Digital Signature Transponder (DST) is a crypto device which offers the challenge/ response functionality. During initialization, the vehicle security system and the transponder exchange a secret encryption key. The key cannot be read out, only the transponder response to a challenge sent by the transceiver can be read. In a typical application, the vehicle security system generates a 40 bit random number (the challenge), and sends it to the transponder using Pulse Width Modulation (PWM). In the transponder the challenge is shifted into the challenge register. For a short period of time, energy is provided by the transceiver and the encryption logic generates a 24 bit response (signature).
The response R is a function of the encryption key Ke , the challenge RAND and the cryptographic algorithm Fc. R=f(Fc, RAND, Ke ).
The response is returned to the transceiver using Frequency Shift Keying (FSK).
The security system calculates the expected response using the same algorithm and the same encryption key and compares the response received from the transponder to the calculated one. The calculation of the expected response can be done simultaneously to the communication between transponder and reader or after reception of the transponder response. If expected and calculated response are equal, the information is sent to the engine management computer. In time critical applications, the challenge and the response can be generated after immobilization and stored for the next cycle.
The advantages of this system are obvious:
Depending on the challenge the response is different every time. The authentication procedure is dynamic.
No portion of the encryption key is ever transmitted after initialization of the transponder
The encryption key cannot be read out
The transponder cannot be duplicated
The encryption key can be irreversibly locked or altered if desired.
The transponder is a complex logical and mechanical micro system designed to operate at very low power. During energy transfer less than 1A is consumed by the transponder IC. This allows a capacitor to be charged over a considerable distance within a reasonable amount of time, typically less than 50ms. Even during the encryption process, the current consumption is below 16A. Therefore, the typical maximum read range is comparable to standard Read Only systems.
The Digital Signature Transponder was based on many established circuit blocks and assembly techniques to ensure compatibility to existing transceiver hardware and to keep existing qualified automated production lines.
Apart from the design challenges for the IC design:
Maintain low power consumption despite the large number of gates for encryption
Keep wiring of the encryption circuitry to a minimum
Keep chip size to a minimum,
A considerable effort has been spent to ensure
A high level of cryptographic security
Fast transaction times for the challenge/response cycle
Low data processing effort for the encryption algorithm in the car security system
Reliability in the application in terms of highly sophisticated supervision circuitry in the transponder.
All encryption algorithms are theoretically breakable. An algorithm is computationally secure if it cannot be broken within a reasonable amount of time respectively with reasonable resources. In this context Ëœreasonableâ„¢ is open to interpretations. Current assumptions for attacks against immobilizer systems are:
The attacker will not spend more than five minutes in the vehicle
The key is not longer than ten days available for analysis
The key is not longer than ten days available for analysis
The attacker is familiar with cryptoanalytical techniques.
Dictionary attacks can be used if the key was available to the attacker for a
certain period of time to build a dictionary of challenge response pairs. In the vehicle, the attacker hopes for a challenge that is already in his dictionary to reply with the correct response and start the engine.
Statistical calculations show that even if the key is available for 10 days and the dictionary is built at a rate of four responses per second, the probability for a successful attack within five minutes in the car is only 0.47%. Taking into consideration that this effort has to be repeated for each vehicle, it can be understood that this method is uneconomic for the thief.
Cryptoanalysis makes use of the knowledge of the algorithm. Those attackers try to find a mathematical solution to the problem of finding the encryption key with a limited amount of challenge response pairs. The algorithm in the Digital Signature Transponder has been developed to frustrate these cryptoanalytical methods.
Read/Write Crypto Transponder for Short Cycle Time
The TK5561A-PP is a complete transponder integrating all important functions for immobilizer and identification systems. It consists of a plastic cube which accommodates the crypto IC and the antenna realized as tuned LC-circuit. It is a R/W crypto transponder for applications which demand higher security levels than those which standard R/W transponders can fulfill. For this reason it has an additional encryption algorithm block which enables a base station to authenticate the transponder. Any attempt to fake the base station with a wrong transponder will be recognized immediately. For authentication, the base station transmits a challenge to the transponder. This challenge is encrypted by both IC and base station .Both should posses the same secret key. Only then the result can be expected to be equal. The on-chip 320 â€œbit EEPROM(10 blocks of 32 bits)can be read and written blockwise by a base station Two or four blocks contain the ID code and six memory blocks are used to store the crypto key as well as the read or write options.125 kHz is the typical operational frequency of a system using this transponder.
The antenna consists of a coil and a capacitor for tuning the circuit to the nominal carrier frequency of 125kHz.The coil has a ferrite core for improving the distance of read, write and programming operations.
The AFE includes all circuits directly connected to the coil. It generates the ICâ„¢s power supply and handles the bidirectional data communication with the base station. It consists of the following blocks:
Rectifiers to generate a DC supply voltage from the AC coil voltage
Field gap detector for data transmission from the base station to the IC.
The controller has the following functions:
Control memory access.
Handle correct write data transmission.
Error detection and error handling.
Control encryption operation.
Control adaptation of resonance frequency.
Power on reset
It is a delay reset which is triggered when the supply voltage is applied.
The IC is able to minimize the tolerance of the resonance frequency between the base station and the transponder by on-chip capacitors in parallel to the LC circuit of the transponder.
The bitrate generator can deliver bitrates of RF/32 and RF/64 for data transmission from the IC to the base station.
The bit decoder forms the signals needed for write operation and decodes the received data bits in the write data stream
The modulator consists of two data recorders. Manchester and biphase modulation are possible.
Voltage pump which generates about 18V for programming of the EEPROM.
The memory is a 320-bit EEPROM which is arranged in 10 blocks of 32 bits each. All 32 bits of a block are programmed simultaneously. The programming voltage is generated on-chip.
The crypto circuit uses an algorithm to encrypt the challenge which is written to the chip. The computed result can be read by the base station. Comparing the encryption results of the base station and the IC, a high security authentication procedure is established.
Writing Data into the IC
A write sequence of the IC is shown below.
Writing data into the transponder occurs by interrupting the RF field with short gaps. After the start gap the write op-code (10) is transmitted. The next 32 bits contain the actual data. The last 4 bits denote the destination block address. If the correct number of bits has been received, the actual data is programmed into the specified memory block. 
Write Data Decoding
The time elapsing between two detected gaps is used to encode the information. As soon as a gap is detected, a counter starts counting the number of field clock cycles until the next gap will be detected. Depending on how many field clocks elapse, the data is regarded as â„¢0â„¢ or â„¢1â„¢.The required number of field clocks is shown in figure .A valid â„¢0â„¢ is assumed if the number of counted clock periods is between 16 and 32, for a valid â„¢1â„¢ it is 48 or 64 respectively. Any other value being detected results in an error and the device exits write mode and returns to read mode.
Principle areas of applications of RFID include:
2. Manufacturing and processing.
Texas Instruments Radio Frequency Identification (TI-RFid) Systems has introduced its new RFID tag for textile rental and dry cleaning applications. TI-RFid tags provide more accurate identification and greater accountability as well as improved handling through each stage of cleaning and processing to final customer delivery.
RFID system allows booksellers to gain such information as the range of books a shopper has browsed, the number of times a particular title was picked up, and even the length of time spent flipping through pages. Gillete ,Wal-Mart, and Tesco will install specially designed shelves that can read RF waves emitted by microchips embedded in millions of their products. The shelves can scan the contents of the shelves and, via computer, alert store employees when supplies are running low or when theft is detected.
RFID tags loaded with biometric information will be embedded in passports to ensure travelers comply with security regulations.
RFID technology is also being used to improve luggage handling in airports.
Certain specific applications of RFID include:
1. Fleet management.
2. Inventory and asset management.
3. Warehouse automation.
4. Hazardous material management.
5. Packaging, security and access control.
6. Smart card payment systems.
RFID technology permits no line of sight reading.
Robustness and reliability under difficult environmental conditions.
These tags can be read through water, snow, concrete, bricks, plastics, wood, and most non-metallic materials
Available in a wide variety of physical forms, shapes, sizes and protective housings.
RFID tags can be read at very high speeds.
In most cases the response time is less than 100ms.
Difficulty in duplicating, offers a high degree of security.
RFID solutions cost much higher than the conventional barcodes. A large fraction of its cost lies in the software infrastructure and the enterprise application and integration
Lack of standardization.
Standardization has not been provided across many fronts, ranging from the different data formats used to interoperatability between RFID readers and tags from different vendors to interference between RFID products from different manufacturers.
RFID will hurt privacy
RFID transponders are forever part of the product, and designed to respond when a signal is received.
RFID tags will soon be tracking millions of consumer products worldwide. Manufacturers will know the exact location of each product they make from the time it is made until it is used and tossed in the recycle bin or trash can. The crypto transponders will be well suited for future generation vehicle entry systems.
The RFID tagging will take off when the cost of the tags drops to one percent of the cost of the product it is applied to, and that date is somewhere near.
2005 is the date that researchers say when radio frequency tagging becomes viable and until then, we must wait and see.
 Jay Warrior, Eric McHenry, Kenneth McGee, They know where you are, IEEE Spectrum, July 2003, pp.21-25
 Ankit Khare, RFID challenges barcoding, PC Quest, April 2003, pp.46
 Andy Emmerson, Tiny tags talk volumes, Everyday Practical Electronics, May 2001, pp.322
 Uma Gupta, RFID and beyond, Electronics For You, October 2003,
 Ulrich Kaiser, Wolfgang Steinhagen, A low-power transponder IC for high- performance identification systems. IEEE Journal Of Solid-State Circuits.Vol.30, March 1995, pp306-310
CLASSIFICATION OF TAGS 3
RANGE AND POWER LEVELS 6
RFID SYSTEM 8
IMMOBILIZER SYSTEM 10