Infrared Data Association
In 1993, around 50 companies came together in the Infrared Data Association ( IrDA ) to establish a forum for the discussion and standardization of infrared transceivers and protocol specifications. Members included HP , IBM and Microsoft .
IrDA specifies standards for optical wireless point-to-point data transmission using infrared light (850 - 900 nm). The focus is on the transmission in the near range with ranges of less than 1 m and a line-of-sight (LOS) connection. IrDA is used, for example, in the Personal Area Network (PAN). IrDA is widely used in laptops , cell phones and PDAs . Advantages of the IrDA standard are the comparatively high data throughput, the high security against eavesdropping due to the short maximum range, the low energy consumption per transmitted byte or the high reliability due to the low bit error rates (BER). Disadvantages arise primarily from the need for a line of sight between the two end points. Important application layers are IrCOMM , IrOBEX , IrSimple , IrFM or IrLAN .
Remote controls in the consumer electronics sector, such as televisions, usually also work with infrared data transmissions. However, their proprietary protocols such as RC-5 differ from the IrDA protocol.
history
As infrared technology spread more and more, there was a growing interest in allowing different, manufacturer- independent devices to communicate with one another via infrared. To make this dream come true, around 50 companies (including Hewlett-Packard, IBM, Digital ) came together in August 1993 and founded the Infrared Data Association (IrDA). The aim was to create a uniform protocol for data transmission via infrared. This should make it possible, for example, to let a printer from Hewlett-Packard communicate with an IBM computer using infrared. Hewlett-Packard was one of the pioneers in the development of infrared data transmission. For this reason, the designation HPSIR (HP-Serial-Infrared) is still used for IrDA 1.0 today.
Specifications
Overview
IrPHY
In the IrPHY layer, the modulator or encoder as well as the framer are specified. The most important properties are:
- Range: Standard: 1 m; Low power: 0.2 m; Standard to low power: 0.3 m
- Opening angle: ± 15 °
- Data rates: 2.4 kbit / s to 1 Gbit / s
- Modulation: none ( baseband )
- Wavelength: 850 - 900 nm
There are different coders and framers for different data rates.
SIR (Serial Infrared)
with 9.6 to 115.2 kbit / s (analogous to UART data rates)
- analogous to UART data rates, RZI, 3/16 pulses
- The data rate of 2.4 kbit / s is optional and is only rarely implemented.
- 9.6 kbit / s is used for the discovery process and connection establishment. After negotiating the corresponding connection parameters, a switch is made to the target data rate.
- 16-bit CRC -CCIT
MIR (Medium Infrared)
with 0.576 Mbit / s and 1.152 Mbit / s
- RZI, 1/4 pulse, HDLC bit stuffing
- 16-bit CRC-CCIT
FIR (Fast Infrared)
with 4 Mbit / s
- 4 Pulse Position Modulation (4PPM)
- 32-bit CRC (IEEE 802)
- maximum frame size: 2 kB
VFIR (Very Fast Infrared)
with 16 Mbit / s
- Non Return to Zero Inverted (NRZI), HHH (1.13) , named after Hirt, Hassner and Heise, the developers
- 32-bit CRC (IEEE 802)
- maximum frame size: 2 kB
UFIR (Ultra Fast Infrared)
with 96 Mbit / s
- NRZI, 8 B10 B code
- 32-bit CRC (IEEE 802)
- maximum frame size: 32 kB
Giga-IR
with 512 Mbit / s and 1 Gbit / s
- 2-ASK: 8 B10 B-Code, 512 Mbit / s, 1 Gbit / s, NRZI
- 4-ASK: modified 8 B10 B-code, 1 Gbit / s, NRZI
- 32-bit CRC (IEEE 802)
- maximum frame size: 64 kB
IrLAP
IrLAP (Infrared Link Access Protocol) ensures reliable transmission of data.
- Access control on the infrared channel
- Determination of communication partners
- Providing a reliable full duplex connection
- Negotiating the distribution of roles (primary-secondary)
IrLMP
IrLMP (Infrared Link Management Protocol) provides several logical channels on a physical connection.
- Provision of several logical connections
- Concealment of roles
IrCOMM
Serial and parallel interfaces are emulated with IrCOMM. A total of four different modes are defined. These are 3-Wire-Raw, 3-Wire, 9-Wire and Centronics. The often known IrLPT is based on 3-Wire-Raw. Two virtual channels are used in IrCOMM for the transmission of data and control information.
- 3-Wire-Raw
- This minimal variant supports only one data channel and has no separate control channel. For flow control is IrLAP used. This interface can be used on both the serial and the parallel port. No data format is transmitted.
- 3-Wire
- This variant has its own control channel and can therefore use its own flow control via TinyTP . Therefore, several virtual connections are possible. This interface can be used on both the serial and the parallel port.
- 9-Wire
- This is the standard variant for emulating the serial interface. The flow control is done via TinyTP . A separate control line transmits information about the data format, further control data such as for own send and receive data, request to send, clear to send etc. are also transferred according to the standard for the serial interface.
- Centronics
- This is the standard variant for emulating the parallel interface. Centronics is an industry standard that has meanwhile become generally accepted for parallel interfaces.
The virtual COM interface used in Microsoft Windows (e.g. available via HyperTerminal ) uses 3-wire mode. In order to use IrDA via the virtual COM interface on Microsoft Windows systems since Windows 2000, IrCOMM2k is necessary.
IrOBEX
With IrOBEX (short OBEX for OB ject EX change) a platform-independent exchange of different objects is possible. Objects are, for example, telephone, calendar and address entries as well as pictures, music files and many others. IrOBEX works in the classic client-server model. It contains rudimentary session management as well as the "PUT" and "GET" methods for data transfer. The OBEX protocol is thus remotely comparable to the File Transfer Protocol . IrOBEX was taken over by Bluetooth and is introduced there as an OBEX profile. According to the OSI model , it belongs to the session layer (layer 5) and is therefore transparent to the actual communication method. The current IrOBEX version is 1.5.
IrSimple / IrSimpleShot
IrSimple was introduced in 2005 and represents an additional acceleration of the well-known IrDA protocol stack. An accelerated discovery process was introduced. In addition, the connection establishment and the actual data transmission have been further optimized. IrSimple is standardized as bidirectional and unidirectional transmission. Areas of application are, for example, the quick transfer of photos to a display device such as a television. Devices with an implemented IrSimple protocol are, for example, cameras. There are also IrSimple-capable USB adapters with data rates of up to 16 Mbit / s (VFIR).
IrMC
Infrared Mobile Communications ( IrMC 1.1) describes and standardizes the general process for synchronizing mobile devices such as cell phones, cameras or tablets. Typical cell phone data such as addresses, phone numbers, appointments or pictures can be exchanged between devices from different manufacturers. For this purpose, it uses deeper services such as IrOBEX or IrCOMM and specifies how these are to be used. The application of this standard is not limited to pure infrared communication, but also to various other transmission paths such as Bluetooth or USB .
Applications
Consumer area
- printer
- Cameras
- Mobile phones
- Multifunction watches
- PDAs
Industry
- Data logger
- Maintenance of on-board computers / industrial PCs
Medical technology
- Telemedical devices
IrDA hardware
Infrared ports for the PC are available with different connections:
Serial interface (RS-232)
Infrared ports with connection to the serial interface (RS-232) of a PC are only available with SIR mode due to their maximum speed.
Motherboard infrared port
Infrared ports can also be connected directly to the PC motherboard . The BIOS often instructs the chipset to use the infrared port connection instead of a serial interface. This means that only SIR is possible. Few motherboards offer higher speeds.
USB
Infrared adapters for the USB connection are available in SIR, MIR, FIR and VFIR speeds. Many FIR infrared adapters only support SIR and FIR mode. MIR mode is supported less often. Since around 2007 the market has been flooded with counterfeits, which at best are able to transmit 115.2 kbit per second.
Most manufacturers of USB-to-IrDA chipsets also offer a version that only handles SIR:
| Manufacturer | Chipset | speed | particularities |
|---|---|---|---|
| SigmaTel | STIr4200 | SIR, MIR, FIR | Windows driver only available, no longer in production |
| STIr4116 | SIR | Drivers available for Mac OS, Linux and Windows | |
| STIr4210 | SIR, MIR, FIR | Drivers available for Mac OS, Linux and Windows | |
| STIr4220 | SIR, MIR, FIR, VFIR | Drivers available for Mac OS, Linux and Windows | |
| KC Technology | IRXpress KC82 C180 | SIR, MIR, FIR | Windows driver only available, no longer in production |
| MosChip | MCS7784 | SIR | Compatible with Polar Electro watches |
| MCS7780 | SIR, MIR, FIR | ||
| MCS7781 | SIR, MIR, FIR |
Built-in infrared ports
Fixed infrared ports in devices are often FIR infrared ports, because, for example, in laptops these are connected via their own chip that supports faster transmission. Other devices with a built-in infrared port (e.g. cell phones or PDAs ) can also have a SIR infrared port built in.
swell
- ↑ Website of the IRDA.ORG. Retrieved January 12, 2013 .
- ↑ Infrared Data Association: Serial Infrared Physical Layer Specification , Version 1.4, 2001
- ^ Charles D. Knutson, Jeffrey M. Brown: IrDA Principles and Protocols. MCL Press, Salem UT 2004. ISBN 0-9753892-0-3
- ↑ UFIR (ultra fast infrared). In: itwissen.info. Retrieved February 6, 2016 .
- ↑ Midori Miller: IrDA Announced New Infrared Wireless Communication of 1 Gigabit / s Speed as Part of Their International Standard Specifications. (No longer available online.) In: FreshNews.com. April 16, 2009, archived from the original on May 16, 2013 ; accessed on January 12, 2013 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Jan Kiszka: IrCOMM2k. In: ircomm2k.de. December 12, 2004, accessed January 12, 2013 .
- ↑ Midori Miller: IrDA Releases OBEX 1.5 Specification for the Next Generation of Wireless Communication. In: Business Wire. February 15, 2010, accessed January 12, 2013 .
- ↑ Digital Cameras> Compatibility> IrSimple ™ & IrSS ™ for Wireless Communications. In: Fujifilm Global. Retrieved January 12, 2013 .
- ↑ Pentax Kr: More speed and less noise. In: fotoMAGAZIN - cameras, lenses, photo practice, photographers. September 9, 2010, accessed January 12, 2013 .
- ↑ IrSimple Products. ACTiSYS Corporation, accessed January 12, 2013 .
- ↑ Infrared Data Communication According to the IrDA® Standard, Part 2: Protocol IrDA Protocol Stack. (PDF, 90.4 kB) Vishay Semiconductors, September 20, 2006, accessed on January 12, 2013 (English).
- ↑ Dschen Reinecke: USB infrared port counterfeiting. In: infrarotport.de. July 2, 2008, accessed January 12, 2013 .
- ↑ Christof Windeck: Counterfeit USB-IrDA adapter. in: c't . Hanover 2007, 17, page 17. ISSN 0724-8679
literature
- Jörg Roth: Mobile Computing. Basics, technology, concepts . dpunkt, Heidelberg 2002, ISBN 3-89864-165-1 .
- Charles D. Knutson, Jeffrey M. Brown: IrDA Principles and Protocols . MCL Press, Salem UT 2004, ISBN 0-9753892-0-3 .
- Thomas Hofmann: Design and investigation of a Giga-IR framer in hardware . VDM Verlag, ISBN 978-3-639-31626-1 .
