Infrared Data Association
In the Infrared Data Association (IrDA ) in 1993, approximately 50 companies have joined forces to establish a forum for the discussion and standardization of infrared transceivers and protocol specifications. Members have included HP, IBM and Microsoft.
IrDA standards specified for the optical wireless point -to-point transmission by means of infra red light ( 850-900 nm). The local transfer at ranges of less than 1 m and a Line -of -Sight ( LOS) connection is in the foreground. IrDA is used for example in the area of Personal Area Network ( PAN). Large dissemination finds IrDA for laptops, mobile phones or PDAs. Advantages of the IrDA standards are the comparatively high data throughput, high protection against eavesdropping due to the low maximum range, the low energy consumption per transmitted byte or the high reliability due to the low bit error rate ( BER). Disadvantages arise primarily through the line of sight. The line of sight between the two end points is required, thus limiting the scope. Important application layer are IrCOMM, IrOBEX, IrSimple, IRFM or IrLAN.
- 3.1 consumer sector
- 3.2 industry
- 3.3 Medical
- 4.1 Serial interface ( RS -232)
- 4.2 Motherboard infrared port
- USB 4.3
History
When the infrared technology used more and more, the interest grew to let communicate different, independent of the manufacturer devices to each other via infrared. To realize this wish, circa 50 companies ( including Hewlett -Packard, IBM, Digital) joined in August 1993 and founded the Infrared Data Association ( IrDA). The goal was to create a uniform protocol for data transmission via infrared. So it should be possible, for example, have them communicate with a printer from Hewlett -Packard with a computer from IBM via infrared. Hewlett- Packard was one of the pioneers in the development of infrared data transmission. For this reason, the term HPSIR (HP Serial Infrared) IrDA 1.0 is still being used today.
Specifications
Survey
IrPHY
In IrPHY layer both modulator and encoder and Framer be specified. The main features are:
- Range: Standard: 1 m; Low power: 0.2 m; Standard for 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
For different data rates, there are different encoder and framer.
SIR ( Serial Infrared )
With from 9.6 to 115.2 kbit / s (similar to the UART data rates)
- Analogous to UART data rates RZI, 3/16-Pulse
- The data rate of 2.4 kbit / s is optional and is only very rarely implemented.
- For the discovery process and the connection 9.6 kbit / s is used. After the negotiation of the connection parameters is changed corresponding to the target data rate.
- 16- bit CRC - CCITT
MIR (Medium Infrared)
At 0.576 Mbit / s and 1.152 Mbit / s
- RZI, 1/4-Pulse, HDLC bit stuffing
- 16- bit CRC - CCITT
FIR ( Fast Infrared )
4 Mbit / s
- 4 Pulse Position Modulation ( 4 PPM )
- 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 )
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
IrCOMM
With IrCOMM serial and parallel interfaces are emulated. There are defined four different modes. These are 3 -Wire raw, 3 -Wire, 9- Wire and Centronics. The often known IrLPT based on 3 -Wire Raw. For the transmission of data and control information, two virtual channels used in IrCOMM.
The virtual COM interface used in Microsoft Windows (eg available via HyperTerminal ) using the 3- wire mode. To use IrDA on the virtual COM port to a Microsoft Windows systems since Windows 2000, IrCOMM2k is necessary.
IrOBEX
With IrOBEX (short for OBEX Object Exchange ) is a platform-independent exchange of different objects is possible. Objects are, for example, phone, 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 transmission. Thus, the OBEX protocol is remotely comparable to the File Transfer Protocol. IrOBEX was acquired by Bluetooth and is introduced there as OBEX profile. The current IrOBEX version is 1.5.
IrSimple / IrSimpleShot
IrSimple was introduced in 2005 and provides an additional acceleration of the known IrDA protocol stack dar. There an accelerated discovery process was introduced. In addition, the connection and the actual data transmission has been further optimized. IrSimple is standardized as bidirectional and unidirectional transmission. Areas of application are, for example, the rapid transfer photos to a display device such as a TV. Devices with implemented IrSimple protocol, such as cameras. There are also IrSimple - capable USB adapter with data rates up to 16 Mbit / s ( VFIR ).
IrMC
Infrared Mobile Communications ( IrMC 1.1) describes and standardizes the general flow for synchronization of mobile devices such as mobile phones, cameras and tablets. Typical mobile phone data such as addresses, phone numbers, dates or images can easily be transferred between devices from different manufacturers. It uses underlying services such as IrOBEX or IrCOMM and specifies how they are to be used. The application of this standard is not limited to pure infrared communication, but also to various other means of transmission, such as Bluetooth or USB.
Applications
Consumer sector
- Printer
- Cameras
- Mobile phones
- Multifunctional Watches
- PDAs
Industry
- Data logger
- Maintenance of on-board computers / industrial PCs
Medical
- Telemedical devices
IrDA hardware
Infrared ports for the PC is available with different connections:
Serial interface ( RS -232)
Infrared port with a connection to the serial interface ( RS- 232 ) of a PC are available on the basis of which the maximum speed only with SIR mode.
Motherboard Infrared port
Infrared ports can also be connected directly to the PC motherboard. Often by the BIOS, the chipset is instructed to place a serial interface to use the infrared port connector. This is only possible SIR. Only a few motherboards offer a higher speed.
USB
Infrared adapter for the USB port is available in speeds of SIR, MIR, FIR and VFIR. Many FIR Infrared adapter only support SIR and FIR mode. The MIR mode is rarely supported. Since about 2007, the market is flooded with fakes that are able at best to transfer 115.2 kbit per second.
Most manufacturers of USB to IrDA chipsets also offer a version that is only capable of SIR:
Fixed infrared ports
Fixed infrared ports in devices are often FIR infrared ports, as for example in laptops these are connected via a separate chip that supports faster transfer. For other devices with built- infrared port (eg mobile phones or PDAs) can also be a SIR infrared port be installed.