FullDive

The use of technology to fully immerse one's conscience in virtual reality. Developed by Kayaba Akihiko it led to the creation of the device called Nerve Gear. It is the basis of most of the stories in the series.

Known VR Technologies

 * Nerve Gear (a.k.a. NERve Direct Linkage Environment System)
 * AmuSphere
 * Medicuboid
 * Soul Translator

Nerve Gear
The Nerve Gear (ナーヴギア) was created by Argus. It completely controls player's consciousness by redirecting the signals the brain sends to the body and sending it's own waves to stimulate the five senses. It has its own battery source, as well as a high frequency electromagnetic microwaves emisor. This design trapped 10,000 players during the official launch of Sword Art Online.

AmuSphere
AmuSphere (アミュスフィア) is the revised version of the Nerve Gera which was developed by [http://swordartonline.wikia.com/wiki/RECTO_Progress_Inc. RECTO Progress Inc.]. The system has been modified to make it safer than it's predecesor by changing the microwaves emisor to a low frequency one and the incorporation of various sensors that continually monitor blood pressure and brain waves which provoke a safety logout feature in case that the person's statuses become abnormal.

Medicuboid
Medicuboid (メディキュボイド) is Amusphere. However, this helmet is used specifically for medical purposes.

Beyond
During the Alicization arc, a new technology is hinted at which is called Brain Machine Interface, or BMI for short, where the mind is accelerated to x times the normal, giving the person the ability to perform processing x times faster in less time. The BMI uses a different FullDive technique. It starts with «Soul Translation». An example the Kirito uses to explain this complexity is of the brain: the synapse is the sole transmitter between neurons, and then goes into a theory: Quantam brain dynamics, which is like the cell frame to support its structure, like a skull. However, it is in a shape of a tube, which has a light particle, or evanescent photon, a quantum. The collection of photons in the computer, is called «Fluctuating Light», shortened to «Fluctlight». The «Soul Translator» translate «Fluctlight», or the words humans understand and write out the information into a form that could be read.

Usage
To use Nerve Gear and AmuSphere, the player places the game console over the head. Then, the player will lay down in a comfortable position. After, the helmet-like game will activate through the words "Link Start".