Visible light communication (VLC) is the use of visible light as a method of wirelessly transmitting data. VLC is an affordable method of transmitting data at light speed. The light used in VLC is between 780-375 nanometers. The majority of modern VLC implementations are digital, but early uses included pre-radio transmission of sound by modulated sunlight in the photophone invented by Alexander Graham Bell in the 1880s.
Although radio frequency is more commonly used for communications, VLC has a number of advantages over the invisible frequencies of radio. VLC offers very low latency and high bandwidth, while radio has both a more limited spectrum and more potential for cross talk and interference than VLC. The limitation of line of sight can also be a security feature, unless a hacker has line of sight to a network device on a private network. If so, it can still be susceptible to an air gap attack from the outside world. Li-Fi is an implementation of wireless networking that uses VLC.
Although VLC technologies have been historically uncommon, the draw of light based communication is strengthening as the proliferation of wireless devices increases and radio's limited spectrum becomes more crowded. The increased draw toward VLC technologies grows because networks, which affect each other in different radio frequencies, cause no interference to VLC. In IoT, VLC tech is being used as a communication method to connect millions of consumer electronics and machine-to-machine (M2M) devices cost-effectively .