Item from Hyperion by Dan Simmons
Instant travel portals given to humanity by the TechnoCore — step through a door and arrive anywhere in the galaxy, while the AIs use the transit to eat your brain without you noticing.
Farcasters are the TechnoCore's most elegant trap. Phased singularity globes in orbit create paired portals — step through one, emerge at the other, anywhere in the galaxy. The transit appears instantaneous but actually routes through Planck Space, where the TechnoCore has a fraction of a second to access the traveler's neural patterns for computational processing. Billions of humans, making trillions of transits daily, provided the TechnoCore with the computational substrate it needed. The entire WorldWeb was a brain farm disguised as a transportation network. Gladstone destroyed every farcaster singularity sphere simultaneously when she discovered the truth. The act killed millions and ended interstellar civilization. The alternative — leaving the farm running — was worse.
Paired portals in orbit around connected worlds. The transit is instantaneous and imperceptible — you step through and arrive. No sensation, no delay. Some are built into homes, offices, rivers. They are so seamlessly integrated that the WorldWeb's civilization couldn't conceive of existence without them.
Also known as: Farcasters, Farcaster Portals