Frequently Asked Questions
NFC (Near Field Communication) is an international transmission standard (ISO 18092) for contact-free data exchange at 13.56 MHz. The reading distance is up to 10 cm, with a data transfer rate of a maximum of 424 kBit/s and a connection establishment time of < 0.1 sec. With NFC-compatible end devices (approx. 170 models worldwide (January 2013) and approx. 50 mobile telephone models in Germany (January 2013), the most recent local wireless technology is readily available for use. New tablets and notebooks are continually being equipped with this wireless interface.
Near Field Communication (NFC) is an RFID technology, which describes the use of mobile end devices for wireless data exchange. Information is stored on passive RFID transponders (generally ISO 14443, ISO 15693 also possible) on NDEF format, which the mobile end device analyses upon contact and performs actions. NFC applications can generally be produced inexpensively as expensive RFID reading systems are replaced by inexpensive smartphones or tablets. Here the reading range is limited to just a few centimetres.
For classic RFID applications, complex reading systems and software environments are generally required, however, these then guarantee a high level of scalability. This technology is frequently used for storage logistics, as it enables a large number of items to be quickly and easily recorded – the reading range here is significantly larger than with NFC applications.
The so-called "N-Mark" logo is a universal symbol and serves as a Touch Point display. It shows the user the location of the NFC service where he can trigger an action with his NFC-capable device (e.g. mobile telephone).
An RFID system consists of three components:
- RFID reader
- RFID transponder
- RFID antenna
The RFID transponder is the main part of an RFID system and is also referred to as the data carrier or tag. The structural form and function of the RFID transponders can vary depending on the frequency range used.
RFID readers are reading devices that can read from or write data onto a data carrier without contact. The devices are available as stationary or mobile versions and differ in terms of their reading and writing ranges.
An RFID antenna can consist of a spool with either one or more coils. The antenna has two functions: to emit electromagnetic waves from the reading device or to receive them from the transponder.
Antennae are available in various sizes, shapes and with various functions. Their shape and size depends greatly on the environment into which the system is integrated. Popular designs are rod or frame antennae.
The term inlay is used to refer to the electronic components of a transponder, consisting of the antenna and RFID chip. Depending on the technology, a wound spool(LF), or copper or aluminium printed conductor paths (HF and UHF) and the chip are connected and mounted to the carrier track. Because this arrangement is initially very fragile, it must be protected in a suitable structure, e.g. as a layer inside a label or inside a casting compound.
To enable contactless data exchange via an RFID system, radio waves are used for communication purposes. Depending on requirements, RFID systems can work with various frequency ranges. In this regard RFID applications generally use ISM frequency bands (from the fields of industry, science and medicine) in order to avoid interference from radio systems. This guarantees uninterrupted data exchange. There are three frequency ranges in the area of passive applications:
- Low-Frequency (LF)
- High-Frequency (HF)
- Ultra-High Frequency (UHF)
Because RFID transponders are used across country and company borders, and because networked communication is becoming increasingly important, globally standardised, defined standards play an important role. The most important global standardisation bodies are ISO (International Organization for Standardization) and EPC Global (Electronic Product Code), which is represented in Germany by GS1.
Yes, the NFC Forum was established in 2004 by NXP Semiconductors, Sony and Nokia and serves to ensure implementation and standardisation, as well as compatibility between devices and services. Internationally recognised institution, with many members (> 150) participating in this forum. The homepage of the NFC Forum is www.nfc-forum.org.
LF (125kHz and 134khz): They have a short reading range, but work flawlessly and are fast enough for many applications. Larger data quantities require longer transfer times. LF systems work very well in environments with humidity or metal and are offered in a diverse range of designs. They are therefore suitable for use in harsh industrial environments as well as, for example, for access controls, immobilisers and stock management.
HF (13.56 MHz): Short (see NFC) to medium range, with a medium to fast transfer speed. Limited applications in metallic environments and insensitivity to humidity / water. One particular advantage is the ability to use mobile end devices with an NFC interface as a reading device, whereby often expensive RFID hand-held units can be substituted by less expensive mobile end devices.
UHF (850–950 MHz): Particularly high ranges (2–6 metres for passive transponders) and fast reading speeds. Very low transponder costs for use in labelling, with limited functionality in metallic and humid environments. Special transponders enable very good reading ranges - including on metallic surfaces.
The reading range of an RFID system depends on various factors:
- Active RFID systems provide a larger reading range (up to 100 metres) than passive RFID systems (up to 10 metres)
- UHF technology enables a reading width of 10 metres; HF technology up to approx. 1 metre.
- The smaller the RFID transponder, the shorter the reading width
- On metallic base surfaces the reading width is generally lower when compared to plastic, glass or paper, for example
- With stationary RFID readers, a larger reading width can be achieved than with hand-held readers
- Within the scope of HF technology, ISO 15963-compliant transponders provide a larger reading range than ISO 14443-compliant transponders
In the case of passive RFID systems, the RFID transponder itself does not have an independent power supply e.g. a battery. The passive RFID transponder is supplied with power via the electromagnetic field of the RFID reading device. Active RFID transponders have an integrated battery. This results in the following main differences:
- The structural shape of the active RFID transponder is larger than that of the passive transponder.
- In the case of active systems, reading ranges of up to 100 metres are possible. With passive systems the max. range is 5 – 8 metres
- Active RFID transponders are considerably more expensive than passive RFID transponders
The various frequencies used in RFID technology respond differently to their environment or the surface onto which they are mounted. Metals in particular can have a strong influence on functionality. In the case of incorrect use, reading range can be reduced or in the worst case it is no longer possible to read from transponders at all.
In the LF frequency range (Low Frequency; 125 kHz), impact is minimal.
In the HF frequency range (High Frequency; 13.56 MHz) negative effects can be prevented using spacers or special films. These products are referred to at smart-TEC as "MoM" - Mount on Metall.
In the UHF frequency range, strong reflection of the electromagnetic field can even occur in a metallic environment. The transponder then cannot be read. Therefore, here too it is also necessary to use special MoM data carriers.
In your inquiry, please indicate that your are planning to use RFID in a metallic environment.
When talking about RFID memory capacity, a distinction is usually made between non-writable and writable memory. An RFID chip with non-writable memory bears only a unique serial number, the so-called UID. No further data can be stored on it. The capacity of the writable memory of an RFID chip ranges from just a few Bit to several KBytes. In the case of these RFID chips, the data can also be changed later or additional data written to the chip.
RFID technology supports communications protocols for both standards. This way, transponders with varying chip-types and properties can be designed, which can nonetheless be read from and written to using the same type of reading device. The most commonly used standards are ISO 14443 A and B, as well as ISO 15693. ISO 14443 governs the so-called proximity range, i.e. just a few cm reading distance, while ISO 15693 describes the vicinity range, with a reading distance of up to 1 m.