How does the NFC reader distinguish between nfc tag1, nfc tag 2, and nfc tag 4?

Near Field Communication (NFC), also known as short-range wireless communication, is a short-distance high-frequency wireless communication technology that allows non-contact point-to-point data transmission between electronic devices ( within ten centimeters) to exchange data. This technology evolved from contact-free radio frequency identification (RFID) and is backward compatible with RFID. It was first developed by Sony and Philips respectively and is mainly used to provide M2M (Machine to Machine) communication in handheld devices such as mobile phones. Due to the natural security of near field communication, NFC technology is considered to have great application prospects in fields such as mobile payment.

NFC chips have mutual communication functions and computing capabilities. The Felica standard also contains encryption logic circuits. The later standards of MIFARE also added an encryption/decryption module (SAM).

The NFC standard is compatible with Sony's FeliCaTM standard, as well as ISO 14443 A and B, which uses Philips' MIFARE standard. In the industry, they are referred to as TypeA, TypeB and TypeF, where A and B are Mifare standards and F is Felica standard.

In order to promote the development and popularization of NFC, the industry created a non-profit standards organization, the NFC Forum, to promote the implementation and standardization of NFC technology and ensure collaboration between devices and services. Currently, the NFC Forum has hundreds of members around the world, including: SONY, Philips, LG, Motorola, NXP, NEC, Samsung, Atoam, Intel, among which Chinese members include China Mobile, Huawei, ZTE, and Taiwan Zhenglong.

Technical Characteristics

Like RFID, NFC information is also transmitted through electromagnetic induction coupling in the wireless frequency part of the spectrum, but there is still a big difference between the two. First of all, NFC is a wireless connection technology that provides easy, safe, and fast communication. Its transmission range is smaller than RFID. The transmission range of RFID can reach several meters or even dozens of meters. However, due to NFC's unique signal attenuation technology, Compared with RFID, NFC has the characteristics of short distance, high bandwidth, and low energy consumption. Secondly, NFC is compatible with existing contactless smart card technology and has become a formal standard supported by more and more major manufacturers. Thirdly, NFC is also a short-range connection protocol that provides easy, safe, fast and automatic communication between various devices. Compared with other connection methods in the wireless world, NFC is a close-range private communication method. Finally, RFID is more commonly used in production, logistics, tracking, and asset management, while NFC plays a huge role in access control, public transportation, mobile payment and other fields.

NFC, infrared, and Bluetooth are all non-contact transmission methods. They have different technical characteristics and can be used for various purposes. There is no difference in the advantages and disadvantages of the technology itself.

NFC mobile phones have built-in NFC chips, which add the function of two-way data transmission compared to RFID that was originally used only as a tag. This advancement makes it more suitable for electronic currency payments; especially what RFID cannot achieve. , mutual authentication and dynamic encryption and one-time key (OTP) can be implemented on NFC. NFC technology supports a variety of applications, including mobile payments and transactions, peer-to-peer communications, and on-the-go information access. Through NFC mobile phones, people can connect with the entertainment services and transactions they want at any place, at any time, through any device, to complete payments, obtain poster information, etc. NFC devices can be used as contactless smart cards, smart card reader and writer terminals, and device-to-device data transmission links. Its applications can be mainly divided into the following four basic types: for payment and ticket purchase, for electronic tickets, Used for smart media and for exchanging and transmitting data.

Comparison of traditional short-range communication

Compared with traditional short-range communication, near-field communication (NFC) has natural security and fast connection establishment. Specific comparison As shown in the following table:

NFC antenna

A kind of near-field coupling antenna. Since the wavelength of 13.56Mhz is very long and the reading and writing distance is very short, the suitable coupling method is magnetic field coupling. The coil is Appropriate coupling method. The industry usually uses magnetic films (such as those produced by TDK and other companies) combined with FPC to make antennas in mobile phones. A new technology is the integration of magnetic film and FPC, also known as magnetic FPC.

Development Prospects

NFC has the characteristics of low cost, ease of use and more intuitiveness, which makes it more potential in certain fields - NFC uses a chip, The combination of an antenna and some software can enable various devices to communicate within a few centimeters, and the cost is only 2 to 3 euros. According to ABIReasearch's latest research on NFC, the NFC market may flourish in mobile handheld devices. ABI estimates that after 2005, smart phones and enhanced handheld devices using NFC chips will appear on the market.

By 2009, such handheld devices will account for more than half of the market. Research firm Strategy Analytics predicts that global contactless payments based on mobile phones will exceed US$36 billion by 2011. If NFC technology can become popular, it will greatly change the way people use many electronic devices, and even change the way they use credit cards, keys and cash. As an emerging technology, NFC roughly summarizes the shortcomings of Bluetooth technology's poor ability to work together. However, its goal is not to completely replace other wireless technologies such as Bluetooth and Wi-Fi, but to complement each other on different occasions and in different fields. Because the data transmission rate of NFC is low, only 212Kbps, it is not suitable for applications that require higher bandwidth such as audio and video streaming.

The so-called conflict between RFID standards and NFC standards is a misunderstanding of NFC. NFC and RFID have similarities in the physical layer, but they themselves and RFID are technologies in two fields. RFID is just a technology for identifying tags through wireless, while NFC is a wireless communication method. This communication method is interactive.

NFC test locations around the world

* USA, Philips Arena Since December 2005, Philips Arena in Atlanta, Georgia, USA Visa and Philips have been working together on a major NFC test since the Arena, allowing fans to easily shop at concessions and apparel stores. In addition, by placing an NFC-enabled mobile phone in front of a poster embedded with an NFC tag, they can also download movie content such as ringtones, wallpapers, screensavers and clippings of their favorite stars and artists. Additional partners include Nokia, Cingular, Visa, Atlanta Spirit, Chase, and ViVOTech.

* Caen, France In October 2005, Philips conducted a major multi-application NFC test in Caen, Normandy, France, in cooperation with France Telecom, Orange, Samsung, LaSer Retail Group and Vinci Park. During the six-month test, 200 Caen residents will use Samsung D500 mobile phones embedded with Philips NFC chips to pay at selected retail points, park equipment and download information on famous tourist attractions, film promotions and cars Shift schedule.

* Taiwan, Taiwan Proximity Mobile Phone Service Since July 2005, Philips has cooperated with Taiwan Proximity Mobile Transaction Service Alliance (PMTSA) to demonstrate a mobile phone service that can use NFC. BenQ mobile phone for secure payments. This can be said to be a milestone in the process of promoting NFC mobile phones to enter Taiwan's public transportation network.

2007 can be described as the year of "application launch" of NFC in mainland China. Starting from August, the Nokia 6131i with built-in NFC chip was publicly sold in several cities including Beijing, Xiamen and Guangzhou. The phone comes pre-downloaded with a transportation card that can be used on the municipal transportation system. Using the phone, users only need to open a prepaid account to buy tickets and shop at certain shopping malls. The Chinese market has huge potential, and the commercial use of NFC in China is undoubtedly exciting news. At present, millions of people in China have used contactless municipal transportation "all-in-one cards" on public transportation, of which 13 million have been sold in Beijing, 6 million have been sold in Guangzhou, and 1.1 million have been sold in Xiamen. . The application of Nokia and the public transportation departments of the above three places has kicked off the commercial use of NFC in a real sense.

NFC tag types

There are four basic NFC tag types, identified by 1 to 4, each with different formats and capacities. The basis of these tag type formats are: ISO 14443 types A and B, Sony FeliCa, which is the international standard for contactless smart cards, and Sony FeliCa, which conforms to the ISO 18092 passive communication mode standard. The advantage of keeping NFC tags as simple as possible is that in many cases the tags can be single-use, such as in posters where the lifespan is short.

Tag1 Type: This type is based on the ISO14443A standard. This type of tag has the ability to be read and re-written, and the user can configure it to be read-only. The storage capacity is 96 bytes, which is sufficient for storing website URLs or other small amounts of data. However, the memory can be expanded to 2k bytes. The communication speed of this type of NFC tag is 106 kbit/s. This type of tag is simple, so it is cost-effective and suitable for many NFC applications [2]

Tag2 Type: This type of tag is also based on ISO14443A and has readable and re-writable capability, the user can configure it to be read-only. Its base memory size is 48 bytes, but can be expanded to 2k bytes. The communication speed is also 106 kbit/s.

Tag3 Type: This type of tag is based on the Sony FeliCa system. It currently has a memory capacity of 2k bytes and a data communication speed of 212 kbit/s.

Therefore, this type of tag is more suitable for more complex applications, although the cost is higher.

Tag4 Type: This type of tag is defined as compatible with ISO14443A and B standards. It is preset as read/rewritable or read-only at the time of manufacture. The memory capacity is up to 32k bytes and the communication speed is between 106 kbit/s and 424 kbit/s.

It can be seen from the above definitions of different tag types that the first two categories and the latter two categories are quite different in terms of memory capacity and composition. Therefore it is unlikely that there will be much overlap in their applications.

Type 1 and 2 tags are binary and can be read/write or read-only. Categories 3 and 4 are read-only, and data is written during production or through a special tag writer.