Telepathic link

Telepathic link was an advanced and uncommon Force power.

Nearly all Force-sensitives with sufficient training could communicate telepathically face-to-face or across short distances. However, a telepathic link, once established, connected two minds much more strongly, allowing communication of thoughts or emotions across vast distances, even from one end of the galaxy to the other. Use of this power was very difficult, and at least one of the parties involved had to be greatly evolved in the use of the Force.

Palpatine regularly used this power to communicate with Mara Jade (and presumably the rest of his Emperor's Hands), issuing commands from his palace on Coruscant to wherever Jade happened to be.

Rin Sakaros also used this power, though much more rarely. Due to the extremely close bond she had with her brother Tariun, Rin was able to speak to him with her mind from across the galaxy, even when she was in the Unknown Regions and he was on Nar Shaddaa. This use of the power seems to have evolved gradually, and may have been an outgrowth of the close connection between the Sakaros siblings, especially after the death of Keltrayu in 101 ABY. However, in 139 ABY Rin deliberately created a telepathic link with Reiko Kaytana, the mother of her baby brother Nagarian, so Reiko could contact her for help against any threat to herself or the child.