Sector 283 was a star sector located near the Badlands. In late 2373, the Cardassian-Dominion alliance began building an artificial wormhole in this sector, in order to provide a link to the Gamma Quadrant and bring in more reinforcements. Building it close to the Badlands, the wormhole was shielded from Starfleet sensors. (TNG - The Dominion War novel: Behind Enemy Lines)