The Infrared Data Association (IrDA) is an industry-driven interest group that was founded in 1994 by around 50 companies. IrDA provides specifications for a complete set of protocols for wireless infrared communications, and the name "IrDA" also refers to that set of protocols. The main reason for using the IrDA protocols had been wireless data transfer over the "last one meter" using point-and-shoot principles. Thus, it has been implemented in portable devices such as mobile telephones, laptops, cameras, printers, and medical devices. The main characteristics of this kind of wireless optical communication are physically secure data transfer, line-of-sight (LOS) and very low bit error rate (BER) that makes it very efficient. Specifications IrPHY The mandatory IrPHY (Infrared Physical Layer Specification) is the physical layer of the IrDA specifications. It comprises optical link definitions, modulation, coding, cyclic redundancy check (CRC) and the framer. Different data rates use different modulation/coding schemes: SIR: 9.6–115.2 kbit/s, asynchronous, RZI, UART-like, 3/16 pulse. To save energy, the pulse width is often minimized to 3/16 of a 115.2KBAUD pulse width. MIR: 0.576–1.152 Mbit/s, RZI, 1/4 pulse, HDLC bit stuffing FIR: 4 Mbit/s, 4PPM VFIR: 16 Mbit/s, NRZ, HHH(1,13) UFIR: 96 Mbit/s, NRZI, 8b/10b GigaIR: 512 Mbit/s – 1 Gbit/s, NRZI, 2-ASK, 4-ASK, 8b/10b Further characteristics are: Range: standard: 2 m; low-power to low-power: 0.2 m; standard to low-power: 0.3 m. The 10 GigaIR also define new usage models that supports higher link distances up to several meters. Angle: minimum cone ±15° Speed: 2.4 kbit/s to 1 Gbit/s Modulation: baseband, no carrier Infrared window (part of the device body transparent to infrared light beam) Wavelength: 850–900 nm The frame size depends on the data rate mostly and varies between 64 B and 64 kB. Additionally, bigger blocks of data can be transferred by sending multiple frames consecutively. This can be adjusted with a parameter called "window size" (1–127). Finally, data blocks up to 8 MB can be sent at once. Combined with a low bit error rate of generally <, that communication could be very efficient compared to other wireless solutions. IrDA transceivers communicate with infrared pulses (samples) in a cone that extends at least 15 degrees half angle off center. The IrDA physical specifications require the lower and upper limits of irradiance such that a signal is visible up to one meter away, but a receiver is not overwhelmed with brightness when a device comes close. In