Editing Light-emitting diode (section)

===Data communication and other signalling===
{{See also|Li-Fi|fibre optics|Visible light communication|Optical disc}}
Light can be used to transmit data and analog signals. For example, lighting white LEDs can be used in systems assisting people to navigate in closed spaces while searching necessary rooms or objects.<ref>{{cite journal|url=http://ntv.ifmo.ru/en/article/11192/chastotnye_harakteristiki_sovremennyh_svetodiodnyh_lyuminofornyh_materialov.htm |title=Frequency characteristics of modern LED phosphor materials |author1=Fudin, M. S. |author2=Mynbaev, K. D. |author3=Aifantis, K. E. |author4=Lipsanen H. |author5=Bougrov, V. E. |author6=Romanov, A. E. |journal=Scientific and Technical Journal of Information Technologies, Mechanics and Optics|volume=14|issue=6|year=2014}}</ref>

[[Assistive listening device]]s in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of [[Optical fiber|fiber optic]] cable, from digital audio over [[TOSLINK]] cables to the very high bandwidth fiber links that form the Internet backbone. For some time, computers were commonly equipped with [[IrDA]] interfaces, which allowed them to send and receive data to nearby machines via infrared.

Because LEDs can [[frequency|cycle on and off]] millions of times per second, very high data bandwidth can be achieved.<ref>{{Cite news|first=Hank |last=Green |url=http://www.ecogeek.org/content/view/2194/74/ |title=Transmitting Data Through LED Light Bulbs |publisher=EcoGeek |date=October 9, 2008 |access-date=February 15, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20081212050729/http://www.ecogeek.org/content/view/2194/74/ |archive-date=December 12, 2008 }}</ref> For that reason, [[visible light communication]] (VLC) has been proposed as an alternative to the increasingly competitive radio bandwidth.<ref name=":4">{{Cite book|last1=Dimitrov|first1=Svilen|url=https://www.cambridge.org/core/books/principles-of-led-light-communications/0528063BAA6863F6B6D61F6FF69F37CB|title=Principles of LED Light Communications: Towards Networked Li-Fi|last2=Haas|first2=Harald|date=2015|publisher=Cambridge University Press|isbn=978-1-107-04942-0|location=Cambridge|doi=10.1017/cbo9781107278929}}</ref> VLC operates in the visible part of the electromagnetic spectrum, so data can be transmitted without occupying the frequencies of radio communications.