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1.1 Simple and stable read and write performance
For magnetic cards, strip cards, and optical cards, the distribution of information in the medium is flat. Therefore, in order to read and write information on the card, both the head and the photo head in the card machine must reciprocate relative to the card. The mechanical structure that satisfies this transmission requirement is undoubtedly complicated, thus greatly increasing the failure rate of the card machine. In addition, since the magnetic card, the strip card or the optical card does not directly perform data access, it is necessary to convert the magnetic signal or the optical signal into a logic level signal by magnetoelectric conversion or photoelectric conversion. Therefore, the signal conversion portion will further increase the complexity of the electrical part of the card machine. For an IC card, its information card is based on a semiconductor circuit. The distribution of information in the medium is understood to be stereoscopic. The card machine is used in direct contact with the card and keeps the two relatively stationary, thus eliminating the need for complicated mechanical transmission structures. On the other hand, the IC card and the card machine directly perform logic level signal communication without performing signal type conversion. This makes the mechanical structure and circuit composition of the card machine much simpler than that of other card types, which will directly reduce the cost of the machine, reduce the maintenance cost, and make the use of the machine more stable and reliable.
1.2 Stability of data storage
Generally, the signal storage time of the magnetic card is about 1 to 2 years, and it needs to be repeatedly refreshed to keep the data from decaying. The number of card readings and writes is limited to thousands of times. More use will not guarantee the stability and reliability of the data. The semiconductor memory currently used for IC cards can guarantee data retention time of more than 10 years, and even 100 years. This allows the card to be used in the event of off-network, as well as the authenticity and reliability of the data. It also reduces the need to refresh and back up data that may be corrupted or lost. On the other hand, the memory card of the IC card can be repeatedly erased and written up to 10,000 times, or even more than 100,000 times. This not only directly increases the card's reusability, but also greatly reduces the cost of distribution caused by multiple card issuances like magnetic cards.
1.3 Large-capacity data storage capacity
The data capacity of the magnetic card is generally only more than 300 bits (the optical card can be used in a large amount, but its application is limited because it is read-only). However, the current storage capacity of commodity IC cards: memory card, up to 4M bits, logical encryption card, up to 16M bits, and for smart cards with CPU type, the storage capacity has reached 64K bytes, and can be sure, with The development of semiconductor technology will increase its capacity every year. This not only enables the IC card to be used for storing biometrics such as photos, fingerprints, sound waves, and visual patterns, which require large-capacity information, but also provides more room for expansion of "one card multi-purpose".
1.4 Multiple encryption technology measures
Although the information on the magnetic card, barcode card or optical card needs to be converted to be recognized, they lack sufficient resilience against the attacks of copy forgery and malicious tampering. For the IC card, a variety of encryption techniques can be used: (1) Hardware logical encryption: that is, the use of unreadable semiconductor password storage, so that the password comparison operation can only be completed within the chip itself. (2) General software logical encryption method: that is, using feature word mixed coding or using clear code plus detection word verification processing method or directly using cipher text encoding, it is convenient to make the information stored in the card achieve better encryption. performance. (3) Strict software encryption method: By selecting the intelligent IC card with CPU, using the computing power and monitoring program of the CPU in the card, various international encryption algorithms (such as DES, RSA, etc.) are applied to the encryption of the card. Processing, so that the security performance of the IC card reaches a fairly high level.
1.5 Intelligent processing and identification capabilities
Light theory is a magnetic card, an optical card or a bar code card, all of which are passive operations without intelligence. The smart IC card not only can actively issue command requests to the interface device, but also authenticates the legitimacy of the interface device, and distinguishes the functions and permissions of the interface device, and has self-calculation and processing capabilities.
1.6 Various compatible functions
Since the substrate shape of the IC card itself conforms to the international standard ID-1 size, and the card base material is the same as the magnetic card, the magnetic card application or the barcode card application can be satisfied by attaching a magnetic card or a printed bar code to the IC card substrate. .
1.7 Good overall cost-effectiveness
At present, the average single-chip cost of an IC card is about 3 to 5 times more expensive than a magnetic card. However, a comprehensive analysis of the comprehensive cost-effectiveness of the IC card system, it is not difficult to see that it has a strong competitive ability, which is mainly reflected in:
(1) The interface device is simple and low in cost (generally 50% lower than the cost of the magnetic card device). At the same time, the maintenance and repair costs of the interface equipment are correspondingly reduced.
(2) The system does not require a large real-time network as a support. It not only reduces the investment for network equipment and engineering, but also reduces the maintenance costs and communication service costs of the system operation.
(3) Good system security, reducing business losses caused by forgery and fraud.
(4) "One card multi-use" reduces the issuance cost of multi-department card issuance and improves the application efficiency of cards.
(5) Stable and long-term data storage time and repeated erase/write times increase the card's multiplexing ability.
(6) The card is used persistently, reducing the issuance cost and management cost of multiple card issuance. In summary, the new product of the IC card has an unquestionable technical advantage compared with other card-based products. With the development of technology, this advantage will be further developed and expanded. Therefore, in the future application of card-based products, the replacement of other cards with IC cards has become the main feature and inevitable trend of future development.
2 Hardware selection in IC card application system
As the hardware device selection of the application system, the system hardware configuration should be considered according to the actual engineering needs and the economic ability of the implementation entity. This mainly involves:
IC card selection and data structure design;
Selection and design of IC card reading and writing equipment;
System data transmission method and network structure selection.
2.1 IC card variety selection
The selection of IC card varieties mainly needs to consider the following aspects:
Card type,
Storage mode,
storage,
Safety requirements,
Comprehensive price factors, etc.
2.1.1 Card type selection
The selection of the card type is mainly selected according to the requirements of the environment environment of the IC card and the operation mode requirements.
A contact type IC card with a contact electrode and a non-contact type IC card with a contactless electrode are two main types of cards.
For situations requiring fast passage and harsh environments (such as dust, rain, darkness, etc.), non-contact IC cards are generally available. Such as the public car charges, traffic road and bridge charges, automatic access control and so on.
The effective distance of the current non-contact type IC card; the read data can reach 1000mm. The write data distance is generally 100 to 200 mm. More typical is the RF Card. It is a passive IC card that is the same size as a contact IC card.
It uses radio frequency to communicate with interface devices. Its effective distance is related to the receiving/transmitting antenna of the interface device.
The basic correspondence is that the working distance is proportional to the area of ​​the antenna.
There are not many varieties of non-contact type IC cards, and Table 1 shows some performances of several non-contact type IC cards.
The average transaction time of a non-contact type IC card is about 0.2 to 0.6 s.
It is worth noting that:
The frequency used by non-contact type IC cards currently lacks clear standard regulations at home and abroad, so it is necessary to pay attention to the standard release dynamics when selecting and using. In addition, it is necessary to avoid interference from non-contact type IC cards such as strong magnetic fields, strong electric fields and other high-frequency sources. At the same time, it is also necessary to pay attention to whether the installation of the IC card device will cause radio frequency pollution to the application environment. Due to the patents and technical complexity of non-contact IC card chip manufacturing, only a few companies in the world can design and produce. Transmit/receive converters (equivalent to read/write devices) used with IC cards are also directly protected by patents. Therefore, the choice of products and system equipment is quite limited. Since most of the cards and cards rely on imports, the price is also high. A front-end transmit/receive converter is about $400 to $600, and a non-contact type IC card costs about $4 to $7 a non-contact type IC card reader device for about $400 to $900.
The contact type IC card is characterized by a wide variety and a wide range of options, and the price of the card and the card machine is much lower than that of the non-contact type card and card machine. In addition, the contact type IC card has no radiation interference problem and has good security and confidentiality. Therefore, the use of contact type IC cards occupies the vast majority of current IC card applications. It can be asserted that due to the requirements for security and confidentiality and the consideration of the electromagnetic environment, it is a non-contact type IC card. Due to the convenience of use, it is also expanding its application range, but the contact type IC card is applied from the application side and the total amount of issuance. It is still in a dominant position. With the development of IC card technology, there is also a dual-purpose card that integrates non-contact and contact IC card chips. It can meet the requirements of two application conditions. On a dedicated card machine, two chips in the card can be completed. Data communication can also be accomplished in different ways to complete data upload, download or transfer. The cost of this new type of multi-purpose card is relatively high, and the price of the matching card machine is relatively expensive.
2.1.2 IC card data storage and processing mode selection
Counting type IC card: The advantage is that the card cost is lower than that of other types of IC cards, and the card machine has lower requirements. Suitable for one-time consumption, it can also use the beautiful printing and advertising on the surface of the card to improve the collection value and other added value of the card itself, so as to reduce the cost of the IC card and system and save investment.
Memory Card or Logical Encryption Memory Card: Applies to cumulative document records or applications that require extensive printing modifications. In particular: the variety of varieties, easy to choose the card with high performance and price ratio, the control operation is simple, the requirements of the card machine and the development system are lower. Can be reused multiple times.
IC card with CPU: For applications with multi-level file management or high density requirements.
2.1.3 Choice of IC card capacity
The memory capacity of the more commonly used CPU type IC card is:
The capacity of the ROM memory is generally between 4k and 16k bytes;
The capacity of the RAM memory is generally between 128 and 512 bytes;
The capacity of the EEPROM memory is generally between 1k and 8k bytes.
Generally speaking, the change in the size of the EEPROM memory has a great influence on the price of the card.
In addition, it should be noted that when selecting the card storage capacity, it is necessary to optimize the filtering of the information to be stored as much as possible, and use various coding methods or code compression techniques to process the records on the card. This not only saves the storage space of the card, but also increases the confidentiality of the card content, thereby making the performance price ratio of the chip higher.
2.1.4 IC card security requirements and options
If the data or document stored in the IC card chip is a public application, it is not necessary to be tampered with or copied by others, and a memory card is generally selected. This is not only because of the low price, but also the capacity of the card from 1k to 4MB word size. In addition, the operation is simple, and the requirements of the system are correspondingly reduced.
If the information stored in the IC card is very important, personal identification is required, and the legitimacy of the read/write interface needs to be recognized. Not only the files and records inside the card need to be controlled by partition layering, but also for each partition or each. The application layer file for authorized password control of various accesses and operations, etc., should select an IC card with a CPU type.
2.1.5 Comprehensive factors of card prices
On the whole, the main factors affecting the price of IC cards are as follows:
(1) Breakthrough of large industrial semiconductor manufacturing process technology below 1 μm and development of stable production capacity.
(2) The actual IC card chip application market demand limits the production scale.
(3) Patent fees of the French Innovatron Group.
At present, the price of a storage type IC card is about 0.8 to 1.6 dollars. The price of the logical encryption type counting card is about 0.6 to 0.9 US dollars, the price of the logical encryption type memory card is about 1.0 to 2.5 US dollars, the price of the IC type with the CPU type is about 3.5 to 8.0 US dollars, and the price of the non-contact type IC card is about 100. 4.5 to 6.5 dollars.
In practical applications, factors affecting IC card prices include: card type, card capacity, order quantity, delivery time, surface printing requirements, and shipping costs.
2.2 IC card reading and writing machine selection
IC card reading and writing machines can be divided into two categories in general:
Dedicated IC card reading and writing machine and universal IC card reading and writing machine.
Dedicated IC card reading and writing machine: For a specific application, it has a complete IC card function that completes the functions of data card read/write exchange, calculation indication, transaction calculation, operation control execution mechanism, etc. between IC card and application system. Read and write equipment or dedicated terminal equipment.
Universal IC card reading and writing:
Generally, it has the function of reading and writing data exchange between the IC card and the IC card. It is not limited to a specific application field, and is usually designed in the form of a standard computer peripheral, that is, an RS-2320 interface conforming to the computer industry standard for its communication input/output channel or an AT-BUS (plug-in board) structure for data input. Output Interface. Such an IC card reader/writer has a direct connection with a microcomputer, and constitutes a microcomputer-based IC card application system.
The general-purpose IC card reading and writing machine can be divided into two forms according to the installation method:
Built-in and external.
(1) Built-in type:
Use the RS-2320 interface of the microcomputer to connect with the implement main board to complete the data exchange. The shape of the machine is often designed as the standard 3′′ floppy disk drive structure, and is installed on the front panel of the chassis by using the peripheral position on the microcomputer chassis. The machine adopts the internal power of the microcomputer. The machine communicates with the microcomputer in serial mode.
(2) External type:
Connect to the machine using the RS-2320 connector on the back of the PC chassis. The reader/writer is placed independently on the desktop or chassis outside the PC chassis. Such implements are typically powered by a separate dedicated AC or DC power source. The advantages of the universal IC card reading and writing machine are that the structure is simple, the price is low, and the application is wide. He relies on the powerful functions of the microcomputer to form various practical application systems or cooperate with the network system, and has completed data acquisition and data exchange of the front end. For the selection of reading and writing implements, the input and output functions of the implement are determined mainly according to the requirements of the actual application. The most important parts include: keyboard function, display function, card deck form, data transmission and communication mode and other auxiliary functions (printout, alarm output, etc.). Another important condition for selecting a card is that the card machine can recognize the type of IC card used. At present, most manufacturers produce tools that can only support reading and writing IC cards of one or a certain system. This is the main obstacle. Therefore, when selecting the machine, be sure to pay attention to the matching IC card.
2.3 IC card deck form selection
In the design of the implement and the practical application requirements, the selection of the deck should mainly consider the following factors:
(1) According to the shape limit of the card machine and the electrical performance requirements, select the service life of the shape of the card seat.
(2) According to the frequency of use of the IC card in use, the number of service life of the card holder is selected.
(3) Consider the degree of influence of the card seat on the performance and appearance of the card caused by the wear of the card during the operation, and select the contact form of the card holder.
(4) Consider whether the cardholder's operation behavior (the operation of the waiter or the cardholder's own operation) in the application system may affect the system security, and choose whether to automatically pop-up control or other auxiliary operation functions.
(5) Consider whether the card in-position signal bit is "normally open" or "normally closed" to better match the circuit design and data acquisition and control of the machine.
The world's major connector manufacturers have developed a variety of IC card series for a variety of applications. Generally, it can be classified according to the contact structure form, the access mode of the IC card, the electrode lead pattern of the card seat, and the in-position detection mode of the IC card.
(1) Classification of contact points: sliding contact method, rolling contact method, probe contact method, and pressing contact method.
(2) According to the card entry and exit operation mode: plug-and-pull, insert-push-in pop-up, push-in-electric control pop-up.
(3) According to the electrode lead method of the card holder, the cable lead-out method and the PCB direct insertion welding method.
(4) According to the "card in place" detection mode of the deck, it is divided into normally open and normally closed.
2.4 Choice of network interface
The network structure here refers to the network connection function supported by the IC card reading and writing machine itself.
In practical application systems, data aggregation and data transmission between IC card terminal devices are also often performed by network communication. A network interface is installed in many dedicated IC card reading and writing implements. Integrating the design of various tools and the actual system usage, the current IC card reading and writing machine itself has a network interface generally RS-232 interface or standard RS-485 interface, which can support a local area network forming a small-range bus structure or a star-line structure. . For an IC card reader/writer with a quasi-RS-232 interface or a standard RS-232 interface, the expansion board is controlled by a multi-user interface together with the microcomputer, and with the support of multi-user software, a network of a small-range star-shaped structure can be constructed. system. The multi-user control expansion board for microcomputers generally has eight or sixteen serial port expansion capabilities. In the actual communication process, the star structure implements a point-to-point communication connection. Communication distance is a problem with the RS-232 interface. The currently available solution is to directly add long-line drivers to increase the drive capability of the interface. For an IC card reader/writer with a standard RS-485 interface, together with a microcomputer, an RS-485 dedicated control expansion board can be used to form a bus structure network system with the support of the corresponding driver software. The RS-485 control board for microcomputers generally has a single or dual port interface. Each single port can be hooked up to 32 terminals. If it is a dual port output, it can take two buses, that is, a total of 64 terminals can be attached. In the bus mode, each terminal device is connected in parallel on the bus, so when the information is transmitted, it is broadcasted. That is, when a device sends information to the bus, all devices on the bus have access to information. But the device that actually gets the information can only be the one that matches the address code of the device with the address specified by the information being transmitted. The direct drive distance of the RS-485 control board is generally up to 1.2km. In summary, in order to achieve the best use of the "one card" system, it is necessary to select the corresponding IC card type, reading and writing equipment, decks and so on. More importantly, a smooth and reliable communication network is formed, which is the standard communication medium.
3 Conclusion
The intelligent IC card is a dazzling new star in the ever-changing information society of the world. It is a change in the market, commodities, currency and trading methods. It will influence and change people's traditional concepts and consumption habits. In the future, we can enjoy the property service and security of vehicle access, parking management, access control management, entertainment consumption, etc. with a smart card, so as to improve the level of property management and create a harmonious and orderly and intelligent intelligence. Atmosphere. The future will be "one card in hand, going all over the world."
"One Card" technology and application
With the continuous development of microelectronic technology, especially the breakthrough and maturity of the memory chip manufacturing process below 1μm, the whole IC card technology has shown more and more vitality.