Teletraan I is the name of the Autobots' computer on board the Ark.
Teletraan I is the supercomputer that is stored upon the Autobot's spacecraft, the Ark. It serves as a principal diagnostic center, a control center, and as a surveillance system through its control of the Sky Spy satellite, as well as a giant database for the Autobots.
Millions of years after crashing down to earth, Teletraan I reactivates after the volcano the Ark had crashed into has a minor eruption. The eruption also triggers one of Teletraan I's protocols, search and repair, which sends out the Sky Spy satellite to scan holographic images of Earth vehicles for the repair part of the protocol, integrating the new vehicle forms into the Transformers' systems as they are repaired. After the first Decepticon (Skywarp) is revived, he immediately restores Megatron, who then orders the rest of the Decepticons to follow. The Decepticons find their way out of the Ark, and Starscream blasts the volcano, causing a rock slide that reseals the exit, trapping the Autobots within. The blast causes Optimus Prime to fall into the line of Teletraan I's repair equipment, which results in his revival as a blue and red semi-trailer. After he is restored, he starts the revival of his companions, the other Autobot warriors.
Throughout the series, there is a sort of running gag, that no matter how badly damaged, no matter how horrible the destruction of Teletraan I is, Teletraan I is always repaired afterwards without much notice and is always back to perfect working order.
In the episode "Kremzeek!" in season 2, Teletraan I is the source of one of the higher-brow moments of humor in the animated series when a malfunctioning Teletraan I mistakenly broadcasts the message, "Choco rations down two grams, doubleplus ungood!" to the confusion of law enforcement authorities. The statement is an allusion to George Orwell's 1984.
Teletraan II was Teletraan I's replacement in the third season of G1, after the Ark and Teletraan I were destroyed by Trypticon. Voice actor Casey Kasem left the series, and Frank Welker became the voice of Teletraan II.
Transformers: Beast Wars
In this series, the Ark was found on Earth by Megatron, and Teletraan I was hijacked by Blackarachnia, who was able to download the access codes into her brain using the Golden Disk, stolen by Megatron.
It is not commonly known that the Autobot's home base computer's name is spelled "Teletraan I" (with Roman numeral one). Misspellings are more commonly used than the true one; "Teletran One" or "Teletran-1" are the ones most frequently encountered (with the latter even making it into the "Ultimate Guide" book). In the Beast Wars: Transformers series finale "Nemesis" Pt.2, Blackarachnia incorrectly pronounced it as "Teletron-I" to which Rattrap quickly and harshly corrected her, "It's Teletraan!" But Blackarachnia simply replies "Whatever!"
Transformers Robots in Disguise
T-Ai is the "daughter" of Teletraan I.
In the 2007 reimagined series, Transformers: Animated, Teletraan I is once again the central computer of the Ark, and serves much the same purpose as in the Generation One series. As Megatron's assault forces the damaged Ark to crash-land on Earth (this time in Lake Erie, near the city of Detroit), the Autobots on board voluntarily go into stasis for their own safety during the crash after ridding themselves of their guest, only to wake up half a century later. From then, the Autobots uses Teletraan One's Sky Spy satellite to scan local vehicles as templates for their vehicle modes on Earth. This version of Teletraan One has a female persona, voiced by Tara Strong. Later in the series in the season 2 finale A Bridge Too Close it is revealed that Teletraan one is simply a system that replaces Omega Supreme (he was offline) and simply controls the ship instead of Omega Supreme.