Personal Access Display Device
In its primary role aboard a starship, the personal access display device (PADD) is a handheld control and display terminal. Small, easily managed terminals and computers are in daily use throughout Starfleet, as a natural response to crew members' needs to (1) execute hardware functions in a variety of locations, and (2) manipulate visual information and communicate that information to others aboard ship. Access to the Enterprise computers and other pieces of equipment can be accomplished through the usual control displays and larger terminal screens, of course, but the PADD has become a convenient adjunct to those panels.
The standard small PADD is 10 x 15 x 1 cm and is constructed from three basic layers of imbedded circuit-composite material. All primary electronics, including multilayer display screen, are bonded to the casing, a boronite whisker epoxy. If dropped accidentally, even from a height of 35 m, a PADD will remain undamaged. Replaceable components are limited to three, the sarium power loop, isolinear memory chip, and subspace transceiver assembly (STA).
In normal daily use, the power supply remains installed and is induction recharged. A full charge will last sixteen hours; if a PADD is about to exhaust its battery, it can set a memory flag in the main computer to transfer tasks to a working unit, or suspend them until a later time. The total memory capacity of the isolinear chips is 4.3 kiloquads. Like the tricorder, the PADD can transfer its total memory to the main computers in less than one second if the need arises. The STA is used to maintain data channels between the PADD and the Enterprise computers. If taken on an away mission, the PADD can also perform uplink/downlink operations and function as a transporter lock-on node. Data transmissions and computing functions can be shared with any other Starfleet device supporting the STA com protocols. As with the personal communicator, transmissions are encrypted for security purposes.
The display screen, 4.25 times larger than that of a tricorder, allows for the manipulation of control graphics, numerical data, and images by touch. Electrosensitive areas of the casing (colored brown on the standard engineering PADD) are designed for specific data movement and storage functions. They can also be used to personalize the default setup and single-crew member security restriction. An audio pickup sensor permits voice input.
The PADD's control functions mimic those of any multilayer panel, insofar as the security restrictions for individual crew members are concerned. Properly configured with the Conn position bridge controls, a crew member can theoretically fly the Enterprise from a PADD while walking down a corridor. While this would be an impractical exercise due to PADD memory limitations and the relatively small display screen, it is an example of the overall multiple-option philosophy established in the Galaxy class starship design objectives by Starfleet's Advanced Starship Design Bureau. This philosophy treats the starship as an integrated organism in which each component can be regarded as a cell in a body directed by a central brain, but with processing capabilities distributed throughout the neural network. Because of this, PADDs and many other handheld data devices are capable of accessing any data file or command program to which the user has authorized access.
Custom PADD configurations can be fabricated aboard the Enterprise or in any starship hardware replication facility equipped with custom isolinear circuit programming capabilities.