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Consumer IR, consumer infrared, or CIR is a class of devices employing the
infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
portion of the
electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...
for
wireless communications Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
. CIR ports are commonly found in
consumer electronics Consumer electronics or home electronics are electronic (analog or digital) equipment intended for everyday use, typically in private homes. Consumer electronics include devices used for entertainment, communications and recreation. Usually r ...
devices such as
television remote control In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as ...
s, PDAs,
laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...
s, and
computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...
s. The functionality of CIR is as broad as the consumer electronics that carry it. For instance, a television remote control can convey a "channel up" command to the television, while a computer might be able to surf the
internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
solely via CIR. The type, speed,
bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...
, and power of the transmitted information depends on the particular CIR protocol employed. CIR is the most common type of
free-space optical communication Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking. "Free space" means air, outer space, vacuum, or ...
.


Protocol description

Since the consumer IR protocols are for the most part not standardized, computers and universal remotes often memorize a bit stream, possibly with compression and possibly without determining the actual bit rate, and play it back. Similarities between remotes are often largely the accidental result of the finite selection of infrared encoder/decoder chips (though now
microcontrollers A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs ( processor cores) along with memory and programmabl ...
are also used) and IR receiver modules or imitation of the older chips rather than by design. Manufacturers of consumer appliances often reuse the same protocol on many similar devices, though for each manufacturer and device type there are usually multiple protocols in use. The code listings inform about for any universal remote.


CIR and protocol implementation

With the ready availability of inexpensive microcontroller chips, many remotes may be based on such chips today rather than dedicated remote control encoder chips. This makes it easier to keep the same codes when moving the buttons on the remote. Also, the decoder functionality will often be integrated into a more complicated microcontroller that controls the AV device, eliminating the need for the separate chip. In the absence of a viable standard, the microcontrollers can be used to emulate the ambiguous protocols used by the old dedicated encoder/decoder chips and it appears that this is often the case. There are even stripped down 4-bit mask-programmable microcontrollers designed only for remote control use (such as NEC's μPD612xA (discontinued), μPD613x, μPD1724x, μPD6x; and μPD17932x 8-bit family). These offer keyboard wake, low power standby modes, and sample controller code though similar features are present on more general
PIC microcontroller PIC (usually pronounced as ''"pick"'') is a family of microcontrollers made by Microchip Technology, derived from the PIC1650"PICmicro Family Tree", PIC16F Seminar Presentation originally developed by General Instrument's Microelectronics ...
s or
Atmel AVR AVR is a family of microcontrollers developed since 1996 by Atmel, acquired by Microchip Technology in 2016. These are modified Harvard architecture 8-bit Reduced instruction set computer, RISC single-chip microcontrollers. AVR was one of the f ...
s.


CIR influences in other devices

Some infrared wireless laptop keyboards and mice use protocols similar to consumer IR devices. Some PC remote controls used for controlling computer media players, controlling presentation software, or other applications also use consumer IR style protocols. Some computer remotes, keyboards, and mice may also use IrDA protocol though
IrDA 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 ...
was designed for very short range use.


Standards

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
manufactured a number of consumer devices of different types that share a common
proprietary protocol In telecommunications, a proprietary protocol is a communications protocol owned by a single organization or individual. Intellectual property rights and enforcement Ownership by a single organization gives the owner the ability to place restricti ...
, called S-link. A
jack Jack may refer to: Places * Jack, Alabama, US, an unincorporated community * Jack, Missouri, US, an unincorporated community * Jack County, Texas, a county in Texas, USA People and fictional characters * Jack (given name), a male given name, ...
on each device allowed the remote control signals to be interconnected between devices. The protocol included the useful but unusual feature of supporting more than one of the same type of device (such as multiple CD changers). Some AV components could generate informational status codes that could be used to do things like automatically stop your tape deck when the CD you were recording stopped playing. Software running on a PC with a suitable interface could also control the AV components and monitor their activity; for example, your computer could tell what disk and track were playing in your CD changer and look up the titles in one of the internet CD databases. Sony charges 5000
USD The United States dollar (symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the official ...
for access to the S-Link documentation.
Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...
use the SIRC protocol for remote controls. SIRC is developed in three different versions: 12 bit, 15 bit and 20 bit. After 12 bits have been received, the receiver waits to see if there are more falling edges to know if the SIRC protocol is 15 bit or 20 bit coded. The RECS-80 and
RC-5 The RC-5 protocol was developed by Philips in the early 1980s as a semi-proprietary consumer IR (infrared) remote control communication protocol for consumer electronics. It was subsequently adopted by most European manufacturers, as well as by ...
codes developed by Philips have been casually referred to as international standards. However, the RECS-80 protocol was prone to interference and was quickly replaced by the RC-5 protocol. Although it appears that they were proprietary protocols developed by
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
, they were also adopted by various other manufacturers, specifically European- and US-based ones. This allowed interoperability between the remote handsets and equipment of various brands. The RC-5 code was, and still is, used by many US- and European-based manufacturers of specialty audio/video equipment. Unfortunately, documentation of the standard commands were not widely distributed. Therefore, there are some brands of equipment that use non-standard commands, causing interference with other equipment also using the RC-5 protocol. The RC-5 command set was defined in the late 1980s and expanded to increase the number of commands in the early 1990s (sometimes called RC-5x). However, the rapidly expanding requirements for newer categories of electronics products since that time (e.g., DVD players, cable boxes, DVR's, et cetera) has led Philips to replace the RC-5 protocol with the newer RC-6 protocol that has both an expanded set of devices (256 versus 32) and commands per device (256 versus 64 in RC-5 and 128 in RC-5x). Again, information on the RC-6 protocol is not readily available from Philips. In contrast, the major Japanese consumer electronics manufacturers almost universally adopted a protocol that was developed and administered by
NEC is a Japanese multinational corporation, multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It prov ...
(now
Renesas is a Japanese semiconductor manufacturer headquartered in Tokyo, Japan, initially incorporated in 2002 as Renesas Technology, the consolidated entity of the semiconductor units of Hitachi and Mitsubishi excluding their dynamic random-access memo ...
). In the NEC protocol, each manufacturer is assigned a unique code that is contained in the transmitted command, avoiding the possibility of false triggering by other remote handsets. RECS-80 uses
pulse-position modulation Pulse-position modulation (PPM) is a form of signal modulation in which ''M'' message bits are encoded by transmitting a single pulse in one of 2^M possible required time shifts. This is repeated every ''T'' seconds, such that the transmitted bi ...
and RC-5 uses bi-phase. Early dedicated-purpose chips were offered by Philips Semiconductors to allow for the easy use of RECS-80 and RC-5 protocols. The SAA3004, SAA3007, and SAA3008 encoder chips used RECS-80, and the SAA3006 and SAA3010 encoder chips used RC-5. The SAA3049A decoder chip decoded either type. (Note that the Philips Semiconductors division is now
NXP Semiconductors NXP Semiconductors N.V. (NXP) is a Dutch semiconductor designer and manufacturer with headquarters in Eindhoven, Netherlands. The company employs approximately 31,000 people in more than 30 countries. NXP reported revenue of $11.06 billion in 2 ...
). All of these chips have been discontinued. However, these transmission protocols are easily created and/or decoded with general-purpose 8-bit microcontrollers, such as those offered by
Microchip Technology Microchip Technology Inc. is a publicly-listed American corporation that manufactures microcontroller, mixed-signal, analog and Flash-IP integrated circuits. Its products include microcontrollers ( PIC, dsPIC, AVR and SAM), Serial EEPROM ...
and
Atmel Atmel Corporation was a creator and manufacturer of semiconductors before being subsumed by Microchip Technology in 2016. Atmel was founded in 1984. The company focused on embedded systems built around microcontrollers. Its products included micr ...
. Transmission of the IR commands requires only a microcontroller and an
infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
LED A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
, available from a wide variety of sources. Reception of the modulated commands for RC-5, RC-6, and the NEC protocols is easily accomplished with specialized IR receivers, most readily available from
Sharp Corporation is a Japanese multinational corporation that designs and manufactures electronic products, headquartered in Sakai-ku, Sakai, Osaka Prefecture. Since 2016 it has been majority owned by the Taiwan-based Foxconn Group. Sharp employs more than 5 ...
and
Vishay Intertechnology Vishay Intertechnology, Inc. is an American manufacturer of discrete semiconductors and passive electronic components founded by Polish-born businessman Felix Zandman. Vishay has manufacturing plants in Israel, Asia, Europe, and the Americas wher ...
. These receivers include a photo-diode, an
automatic gain control Automatic gain control (AGC) is a closed-loop feedback regulating circuit in an amplifier or chain of amplifiers, the purpose of which is to maintain a suitable signal amplitude at its output, despite variation of the signal amplitude at the inpu ...
(AGC) circuit, and a demodulator. The demodulated signal is then decoded with a microcontroller. CEA-931-B defines a method for encapsulating remote control codes over IP and CEA-931-A defines a method for encapsulating remote control codes over
IEEE 1394 IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony an ...
. These documents are not free even though free standards are the norm for Internet Protocols and contributed significantly to their widespread adoption.


Protocol limitations

The lack of standardization creates many problems for consumers: the need to purchase universal remotes because the original cannot control related functions on interconnected devices and to upgrade them when buying a new device, universal remotes that do not adequately control the devices, inability to control more than one of the same type unit, the inability in most consumer setups to stop tape recording when CD ends, the inability of VCRs to control cable channels, and owning more than 5 different remotes.


Technical information

* Infrared wavelength: around 870 nm and 930–950 nm.http://www.vishay.com/docs/82486/tsmp58138.pdf The latter is preferred, because water in atmosphere blocks sunlight in this wavelength, making devices less susceptible to blinding. *
Carrier frequency In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an information-bearing signal for the purpose of conveying information. This carrier wave usually has a m ...
: Usually a fixed carrier frequency, typically somewhere between 33 and 40 kHz or 50 to 60 kHz. The most commonly used protocol is the NEC protocol, which specifies a carrier frequency of 38 kHz. The NEC protocol is used by the vast majority of Japanese-manufactured consumer electronics. The Philips RC-5 and RC-6 protocols both specify a carrier frequency of 36 kHz. However, the early RC-5 encoding chips divided the master frequency of the 4-bit microcontroller by 12. This required a ceramic resonator of 432 kHz to achieve a 36 kHz carrier, which was not widely available. Many companies therefore used a 455 kHz ceramic resonator, which is commonplace due to that frequency being used in the
intermediate frequency In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier sign ...
stages of
AM broadcasting AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmis ...
radios, resulting in a carrier frequency of 37.92 kHz (essentially 38 kHz). Even documentation for Philips' own controller chips recommended an easier-to-obtain 429 kHz ceramic resonator, yielding a carrier frequency of 35.75 kHz. Modern IR transmitters typically use 8-bit microcontrollers with a 4 MHz master clock frequency, allowing a nearly arbitrary selection of the carrier frequency. * Modulation schemes: typically 100%
amplitude-shift keying Amplitude-shift keying (ASK) is a form of amplitude modulation that represents digital data as variations in the amplitude of a carrier wave. In an ASK system, a symbol, representing one or more bits, is sent by transmitting a fixed-amplitude car ...
(ASK). It may also involve
pulse-position modulation Pulse-position modulation (PPM) is a form of signal modulation in which ''M'' message bits are encoded by transmitting a single pulse in one of 2^M possible required time shifts. This is repeated every ''T'' seconds, such that the transmitted bi ...
, biphase/
manchester Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
encoding, etc. of the transmitted pulses (as opposed to the carrier itself). Most remotes use the length of the space between pulses to encode data. * Data rate: usually significantly lower than the carrier frequency. Most protocols seem to range between 120 bits/second and 4 bits/second. The data rate may be variable as some common bit encoding schemes vary the timing between pulses to distinguish between a 1 and 0. * Encoding: varies based on encoder/decoder chips used. It usually includes some redundancy for error detection or correction. For example, some NEC chips send the same code four times (inverted the second and fourth time). * Key to code mapping: varies from remote control to remote control. In many cases, the codes sent may have more to do with the row and column positions on the remote than any unified plan.


See also

*
IrDA 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 ...
*
Remote control In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as ...


References


External links


How to build a USB remote control infrared receiver for PCs

Open S-link

LIRC (Linux Infrared Remote Control)





Library to encode/decode CIR
{{DEFAULTSORT:Consumer Ir Infrared technology