Dummy Barrier: Basic piece of computer security tech which works with Access Jacks or Skinlink. It comes with it's own length of Fiberoptic Cable installed. While active, the unit acts as a buffer between the user and potentially hostile computer systems, with specially configured data inputs and outputs so that in order for a hacker or virus to access the original user's Mesh Inserts or Cyberbrain, they must first completely subvert the Dummy Barrier before being able to access, while the Barrier itself is meant to be quickly ejected in a pinch. The system typically contains no other data than the interface system, and is designed so that an AI can be placed on it to monitor and actively defend the Dummy Barrier. [Low]
The Dummy Barrier is a device which has it's roots in the early days of Cyberbrain technology. Based on ideas from several old entries into cyberpunk fiction, the Dummy Barrier was envisioned as a way to shield a user from accessing a computer system which might contain an active defender or malware which could attack the Cyberbrain of an intruder. It would also act as a buffer to catch any quick and dirty uploads of "Black ICE" or Scorcher programs lying around, and be disconnected relatively quickly (Typically, a Dummy Barrier can be safely ejected as a Quick Action). Usually designed as a big plugbox or some kind of neckband or necklace, the Dummy Barrier also served as a physical obstacle to others wanting to access somebody's Access Jacks - such as with a Disabler (p. 316 EP).
However, the Dummy Barrier was usually a fairly niche device until after the Fall, at which time transhumanity received several grim reminders about information security, and the proportion of people with cyberbrains drastically increased. This has let to a resurgence in use of the Dummy Barrier, mostly for InfoSec professionals, but also for some data miners and scavengers, covert operatives and of course criminals of all stripes. Due to this revitalization, variants of the Dummy Barrier which utilize Skinlink technology are increasingly common. Firewall heavy recommends use of Dummy Barriers along with Analog Tools (p. 176 Firewall) to insulate Sentinels against potentially infected or TITAN-trapped computer systems.