PADDs were used by such space-faring organizations as Earth Starfleet and the later Federation Starfleet, as well as by the Andorian Imperial Guard, Bajoran Militia, Cardassian Union, Klingon Empire, Romulan Star Empire, and Vulcan High Command. They were common to cultures even as distant as the Delta Quadrant.
Consisting of a large touchscreen display and minimalistic manual interface or control panel (generally only one or two buttons), the typical PADD is used for a variety of functions including logging manifests, compiling duty rosters or diagnostic reports, entering personal data, and/or accessing library computer systems.
Varying in size, shape and specification, PADDs are often distinguished by the species of their manufacturer or user, Earth and Federation Starfleet PADDs generally flat and rectangular in shape, Klingon and Cardassian PADDs often more angular.
- The internal circuitry of the Starfleet issue PADD circa 2360s was revealed only once, in the TNG episode "A Fistful of Datas". While the Star Trek: Deep Space Nine Technical Manual indicated isolinear innards, the aforementioned episode portrayed a PADD utilizing printed circuit boards just like present-day computers.
- The Star Trek: The Next Generation Technical Manual states that Starfleet PADDs are powered by sarium-krellide power cells, and have an outer casing of Boronite whisker epoxy, which would allow the PADD to sustain a 35 meter drop without damage.
Standard issue during the 22nd century, PADDs utilized by Earth Starfleet were rectangular in shape, dominated by a large display screen taking up much of the surface area of the device. Small buttons were located just below the screen, most often grouped in two, at the lower right-hand side of the interface. Varying control button arrangements were also in use. (ENT: "Vox Sola", "Dead Stop")
At some point between 2144 and 2154, Arik Soong was able to open all the locks in the San Francisco prison he was being held at using just a PADD. After this incident, he was only allowed to use paper when sketching and writing his ideas. (ENT: "Borderland")
- The prop used throughout the run of Enterprise was not referred to by name until the fourth season episode "Borderland". It was created from a Cabin Light Box (Cabin Pocket-Vue CL-5000P Pocket Light Box), a device used to view transparencies or undeveloped film, augmented with 3M Rubber "Bumpons" for buttons, and a rubber "bumper" for what has been presumed to be a camera. A tutorial for a homemade version can be found online .
- One of these PADDs is currently located in the Star Trek: The Experience museum in Las Vegas, Nevada, while another traveled with the Star Trek Adventure exhibit.
One of the most oft used devices employed by personnel serving in the Federation Starfleet, PADDs were common aboard Federation starships, space stations, and planetary facilities during the 23rd and 24th centuries.
First appearing as late as 2266 aboard such starship types as the Constitution-class vessel, PADDs of the 2260s were large, wedge-shaped devices, operated almost exclusively through the use of a stylus. These data PADDs were often carried by yeomen aboard starships, but appeared in other locations including Starfleet's Starbase 11. (TOS: "The Man Trap", "The Menagerie, Part I", "The Menagerie, Part II", DS9: "Trials and Tribble-ations")
- While it has never been explicitly referred to as a PADD in any of the Star Trek series or films, the Star Trek Encyclopedia uses this device, as well as the clear, PADD-like device carried by Chekov in Star Trek VI: The Undiscovered Country, to illustrate its small section on PADDs. Before the first appearance of the TOS PADD in the first aired episode, a clipboard was used for the same task in "The Cage".
By 2364, PADDs had taken on a smaller profile and, while some models would include one, the stylus was replaced by simple, touch-sensitive controls, generally located beneath a small, square-shaped display screen. Generally small and light-weight, the PADDs of the 2360s and 2370s were basically rectangular in shape, but varied in size, proportion, and even color - ranging from gray and muted blue colors, to red. Some PADDs, like the one used by Dr. Lewis Zimmerman aboard Jupiter Station in 2376, were translucent. (TNG: "Encounter at Farpoint", DS9: "Emissary", VOY: "Caretaker", "Life Line", et al.)
While the common function of these Federation PADDs was most often straight forward data entry or data retrieval, some PADDs were capable of more artistic tasks. Some PADDs, often larger in size than most of their counterparts, were used to draw up schematics or to create composite images or artwork. PADDs were also capable of predictive text functions, allowing users to enter a small amount of data to achieve full words or even sentences. (DS9: "Babel (episode)", "The House of Quark", "Image in the Sand")
- PADDs as they were seen in the spin-off series were designed during the pre-production stage of Star Trek: The Next Generation, at least in part by Rick Sternbach. An early drawing (bearing a strong resemblance to the prop used well into Star Trek: Voyager) can be seen in the book, Star Trek: The Next Generation - The Continuing Mission, dated 17 March 1987. Not long after their debut in TNG, PADDs became a real-life technology with the introduction of the Apple Newton; Palm Pilots being a similar device common in the world of the present.
- Unlike their real world counterparts, most PADDs on TNG, DS9 and Voyager were nonfunctional, rarely even incorporating lighted display screens, but rather printed "Okudagrams". Lighted PADDs did eventually make their way to screens for Star Trek: Insurrection, with custom and store-bought devices like the Cabin Light Box, being used through Star Trek Nemesis and into Enterprise.
Andorian Imperial Guard
Roughly the same size as their Earth Starfleet counterparts, PADDs used by officers in the service of the Andorian Imperial Guard were rectangular in shape, highlighted by several square-shaped pieces at the sides and top which itself was rounded.
- Likely a redress of an existing PADD from Enterprise, the Andorian PADD from "United" was a functional light box, likely of the same make as those used to construct the Starfleet versions.
In use during the 24th century aboard Bajoran spacecraft and stations (including starbase Deep Space 9), Bajoran PADDs were small, roughly oval-shaped devices, nearly the same size as (though slimmer than) the small Federation PADD variant.
Capable of the same general function as their alien counterparts, Bajoran PADDs could be used to download information from primary computer sources, including text documents as large as novels. They were also able to display information in Bajoran as well as other languages, including Federation standard. (DS9: "Emissary", "Shadows and Symbols")
At least two models of data PADDs were used by warriors in the service of the Klingon Defense Force during the 24th century.
Both harshly angular compared to their Federation counterparts, Klingon PADDs came in hand-held and larger, landscape-style varieties. Both displaying information in Klingonese, these PADDs could be found in the chambers of the Klingon High Council on Qo'noS as well as aboard Klingon vessels such as the IKS Rotarran.
The smaller model was dark green in color and featured several button controls running up the center of the device to a rectangular-shaped display screen. The larger model was brown and was held horizontally with a handle attached to the left of an angular, touch screen display. (DS9: "The House of Quark", "Soldiers of the Empire", "Tacking into the Wind")
- Detailed photographs of both Klingon PADDs has surfaced online, notably at one prop manufacturer's website  .
Golden-brown in color, these PADDs were roughly the same size as their Alpha/Beta Quadrant counterparts, but featured circular display screens with several button controls below. Among their functions, they were used to display missing persons reports. (VOY: "Workforce", "Workforce, Part II")
- The Quarren PADD was later slightly modified to appear as a Tellarite PADD, seen on a table in ENT: "Terra Prime".
- The Vulcan PADD featured most prominently in "Stigma" was in fact a repaint of the Bajoran PADD seen throughout Star Trek: Deep Space Nine. This was the only episode in which Vulcan PADDs were featured.