Communication node

From Tardis Wiki, the free Doctor Who reference

A communication node was "a telepathic conduit to an intergalactic trans-dimensional network, whose users can comment on anyone and anything in time and space, without moving from where or when they are". It resembled a crimson jewel. The Master had given a communication node to Susan Foreman, an old family friend of his before Susan left Gallifrey, and intended to find the Doctor with it after the First Doctor left Gallifrey with Susan. Adric thought it was "a bit like the Facebook". (AUDIO: The Toy)