TG tablet

A TG tablet was a handheld computer with full trans-galactic internet access through a thought toggle at the back. It spoke out loud, and had voice recognition built in. It had a thought lock for protection.

Though not stated in the story, it would seem likely based on evidence that "TG" stands for "Thought Toggle".

Ace used such a device, which had been found by UNIT in the Forge's base, to defeat Nobody No-One. She had her potential fiancé Henry Noone write a story about the two married for ten years, thereby creating Dorothy Noone, a being too made of words and with essentially the same name as No-One. After she, together with the Seventh Doctor and Evelyn Smythe, defeated the Word Lord, the Doctor wiped Ace's TG tablet's harddrive clean, much to her dismay. (AUDIO: A Death in the Family)