Biology[edit | edit source]
The headjacks were located at the base of the skull, just above where the neck meets the back of the head. Approximately 1 inch (2.54 cm) in diameter, it provided room within the otherwise close quarters of the human cranium for a data probe approximately 8 inches (20 cm) in length and 0.79 inches (2 cm) in diameter.
These were installed during the synthetic humans' fetal stages and altogether redirected the brain's signals into any data probe plugged into the headjack.
Purpose[edit | edit source]
The headjack was the interface used to primarily connect to the Matrix. More than just connecting to the Matrix, however, the headjack was also used by redpills to connect to any compatible simulated reality like the Construct. Once a redpill was connected to either the Matrix or the Construct, the headjack could then be used to upload data directly into the human brain. This was used by the Resistance to great effect, uploading instructional information to support agents during training and even during mission proper. Some examples of the upload-able information used by the operatives were gun handling, a range of self defense and martial arts techniques, and helicopter piloting.
The manner by which the headjack and data probe worked had not been sufficiently described. But communication by the headjack was probably a mixture of electrical and electromagnetic transmissions, where the headjack was the central interface, with perhaps thousands of tiny connectors or electrodes that meld into and throughout the synthetic brain, or woven through the central nervous system at the brain stem.
Common usage[edit | edit source]
Bluepills[edit | edit source]
Bluepills, human beings still hardwired into the Matrix via pods in the power plant, had their headjacks in non-stop use and did not know of its existence, effectively imprisoning the bluepill within the Matrix. As humanity was only expected to be disconnected from the Matrix upon death, the pod's data probe was very securely attached to the headjack.
Redpills[edit | edit source]
Whenever a redpill was freed from the Matrix, a docbot was summoned, which proceeded to unpleasantly disconnect the data probe from the headjack, also disconnecting the rest of the tubes connected from the pod to the ports found along the body. The redpill, being assumed dead or dying, was then flushed into the sewers.
Jacking in[edit | edit source]
Main article: Jacking in
Redpills continued to use their headjacks to reconnect and access the Matrix for periodic missions as part of their rebellion against the Machines. This was done via data probes similar to the pod's, but less securely attached, only being secure enough to prevent accidental removal. When the headjack was not being used, it was simply left as is.
The initial reinsertion of a data probe into a headjack did not appear to be an altogether pleasant sensation, though not necessarily painful. Morpheus warned Neo that the insertion of the data probe into his headjack for the first time outside the pod would "feel a little weird."
When an individual had a headjack inserted and was in the Matrix or any other virtual location, their body was vulnerable to physical harm and tampering. Notably, if a headjack was removed by somebody in the Real World before the individual could exit using a hardline, they suffered instantaneous death by unknown causes, presumably massive neural damage, killing the RSI which remained in the Matrix. This prevented any individual from simultaneously having his consciousness exist in both the Matrix and the Real World but still coupled the mind with the body. This prevented anyone with a physical body connected to the Matrix to continue existing within the Matrix after the physical body died. Switch and Apoc of the Nebuchadnezzar crew suffered instantaneous death at the hands of Cypher who, while the two were still in the Matrix, forcefully disconnected their headjacks, instantly killing them both in the Real World. Meanwhile, their RSIs simply collapsed dead inside the Matrix without disappearing. Normally, the RSIs disappeared from the Matrix after the redpill disconnected using hardlines.
Trivia[edit | edit source]
- As implied in the original script of The Matrix, the humans not only provide electrical power, but their brains become part of a massive biocomputing cluster that generates and maintains much of the Matrix itself.