In telecommunication

Telecommunication

Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

, Open fiber control is a protocol

Communications protocol

A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...

 to ensure that both ends of a fiber optic cable are connected before laser

Laser

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 signals are transmitted in order to protect people from eye

Human eye

The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...

damage. When a device is turned on, it sends out low powered light. If it does not receive light back, it assumes that the fiber is not connected. When it receives light, it assumes that both ends of the fiber are connected and it switches the laser to full power. If one of the devices stops receiving light, it will revert to the low power mode.