The TT-40 librarian droid was a type of library droid manufactured by the TelBrinTel Corporation with the purpose of providing on-demand information access. Due to its design focus, it possessed a limited data storage capacity and lacked encryption capabilities. The TT-40 was frequently observed in public areas like corporate reception areas and municipal record repositories.
The TT-40 featured a broad base utilizing a repulsorlift engine; this base also functioned as a data terminal, enabling users to make information inquiries from any direction. Users could input searches either by typing on multiple keyboards or by speaking directly to the droid. The droid's main body was supported by this base and contained a switchboard assembly that used a specialized TelBrinTel interface that was not a regular dataport, along with three data wheels equipped with retractable probes. These wheels rapidly rotated between sockets, extending and retracting their probes to connect with the switchboard. This process allowed the droid to retrieve requested information from the central mainframe of the city or corporation via dual ceiling-support connection cables. The final search results could be downloaded to a datapad, printed on flimsiplast, or delivered audibly via the droid's vocabulator.
Early in their production, TT-40 droids were quite costly; however, they were often financially supported by government programs or large corporations to promote education. A fee was sometimes applied for particularly long searches or when accessing data from restricted archives. Although the droids possessed personalities, they were solely focused on information retrieval and were only known by their official designations, such as "Recorder of Assignments and Transactions for the Supervisor's Committee." They could be curt with individuals whose requests lacked sufficient bureaucratic formality, and TelBrinTel made no effort to improve their officious demeanor.
During the Black Fleet Crisis, Luke Skywalker and his companion Akanah came across a TT-40 unit within the city of Griann on the planet Teyr. By utilizing the droid to gain access to the Teyr Central Directories, they successfully narrowed their search for the Fallannassi to the city of Sodonna.