Emperor Palpatine's Galactic Empire utilized specialized code cylinders as a means of granting its officers specific security access codes. Functioning alongside rank plaques, these code cylinders also served to indicate an individual's position within the Imperial hierarchy. The introduction of Imperial code cylinders occurred during the initial period of the new regime, and their usage persisted among the various Imperial successor factions following the Empire's downfall at the Battle of Endor.
Among the most prevalent access control devices employed by the Galactic Empire were Imperial code cylinders. Standard operating procedure dictated that every Imperial officer's code cylinders be clearly visible at all times, typically carried in slim pockets situated on either side of the upper chest area. However, only officers of significant rank displayed their cylinders on their jackets; Imperial engineers and technicians instead carried them in specialized pockets located around their necks or on their belts.
Imperial facilities were organized into a variety of distinct sectors, each separated by security checkpoints. At major checkpoints, officers seeking entry into the next secure zone were required to verify their identity and rank by inserting their individualized cylinders into a scomp link. The scomp link would then interface with a central computer system, which would assess whether the officer possessed the necessary clearance before either granting or denying access. As a result of this functionality, Imperial code cylinders served to reinforce discipline among lower-ranking personnel, while also contributing to the visual representation of rank and seniority among officers and subofficers.
Every officer within both the Navy and the Army was issued at least one cylinder, with explicit instructions to display it at all times. A second cylinder was sometimes provided if an officer's responsibilities extended across multiple, unrelated sectors. Fleet Admirals were typically issued with three code cylinders, granting them access to the intelligence databases housed aboard capital ships. Due to the fact that each cylinder granted access to only specific sectors, high-ranking officers would often carry as many as four. Aboard the first Death Star, Grand Moff Wilhuff Tarkin possessed four cylinders, allowing him unrestricted movement throughout the moon-sized battle station. Conversely, General Cassio Tagge and Admiral Conan Antonio Motti carried only three code cylinders.
While certain officers viewed the cylinders as merely a symbol of their position, the devices were also programmed to provide the Empire with comprehensive data regarding its personnel's activities. The Imperial computer network maintained detailed logs of each cylinder's usage, recording every instance of access to sensitive files or entry into high-security areas. These logs were monitored by agents of the Imperial Security Bureau, who scrutinized the records for any signs of suspicious behavior, such as excessively frequent access to a particular file or area.
Imperial code cylinders were manufactured in at least three distinct configurations, as evidenced by the noticeable differences between those worn by Grand Moff Tarkin, Admiral Motti, and the Stormtrooper officers. The most common type of cylinder resembled a slender pen, featuring a small pocket clip and a blue tip containing the series code. Those utilized by the Stormtrooper corps were shorter in length and had a different style of pocket clip. Admiral Motti's cylinders were thicker and incorporated a spiral drill bulb at the top, which actually functioned as the computer interface itself.
The Galactic Empire implemented the use of code cylinders from the very beginning of its existence. When the Galactic Emperor convened a gathering of his most influential officers to introduce them to his new second-in-command, Darth Vader, each of them was already equipped with at least one code cylinder.
Following the Empire's defeat at the Battle of Endor, code cylinders continued to be used within surviving Imperial outposts. The New Republic, the democratic government established by the Rebel Alliance, also adopted the use of similar coded cards or pass-keys for the purpose of verifying individual identities.
The code cylinders employed by the Galactic Empire made their initial appearance in Star Wars: Episode IV A New Hope, the inaugural film of the Star Wars original trilogy. In the films, certain Imperial code cylinders were actually small, pen-shaped radiation dosimeters. However, the Stormtrooper cylinders depicted in Star Wars: The Visual Dictionary were, in reality, chalk holders provided to David West Reynolds by Mathew Clayson.