In earlier editions, direct neural interface technology enabled humans and metahumans to directly access computers and the Matrix, the ingame global computer network restructured after the 2029 Crash. Access to the Matrix was accomplished by "deckers": individuals that have "cyberdecks". These interface machines are connected to the brain through a Datajack generally located at the temple or behind the ear.
In Shadowrun 4th edition, the Matrix rules have changed, thanks to the setting's constant evolution and a drive to match real world technological developments. After the second Matrix crash in 2064, Matrix technology was moved away from the wired network and led into a wireless technology. The most noticeable difference between the Matrix in the 2070s and the earlier editions is that wireless technology has become completely ubiquitous. Communications and Matrix access is provided through wi-fi nodes placed throughout the infrastructure of just about every city on Earth, fulfilling a service similar to contemporary cell towers - but as these nodes are as numerous as telephone poles, only a tiny percentage of their range is necessary. The nodes of all electronic devices a person carries are connected in a similar manner, creating a Personal Area Network (PAN). People access their PAN with their Commlink, a combination personal computer/cell phone/PDA/wireless device available either as an implant or a head-mounted display. This access can be the total sensory immersion common to cyberpunk fiction, or a sensory enhancement by which the virtual features of one's physical surroundings can be perceived and manipulated. The Matrix of the 2070s is thus not only a virtual reality, but an augmented or mixed reality.
Cyberdecks are obsolete, so "deckers" have once again become "hackers". In turn, the otaku of previous versions (deckers who did not need decks to access the Matrix) have been reworked into technomancers, who possess an innate connection to the Matrix that permits them to access the wireless network without hardware.