The Iconian gateway was a technology developed by the ancient Iconians, whose underlying principles remain well beyond Federation science. The gateway allowed instantaneous travel over enormous distances, at least 70,000 light years. Physically the gateway appeared literally as a "door", either suspended in space or surrounded by a frame, through which was the destination. An individual could simply step through the gateway (as they would an ordinary door) and emerge on the other side. The gateway network allowed the Iconians to travel throughout the galaxy without the use of starships and was the chief means through which they controlled their vast empire, earning them a reputation among their primitive subject peoples as "Demons of Air and Darkness."
Only two Iconian gateways were known to have survived the destruction of the Iconian civilization, both of which were later destroyed. The first was found in 2365 inside the only remaining structure on the surface of Iconia, and was accidentally activated by Lieutenant Commander Data as he was investigating the Iconian controls. The gateway apparently acquired possible destinations automatically, including the USS Enterprise-D and the IRW Haakona. The Enterprise-D away team used the gateway to escape, destroying the facility behind them to prevent it from falling into Romulan hands. (TNG: "Contagion")
The second gateway was discovered in 2372 by the Dominion inside a stone ziggurat on the planet Vandros IV in the Gamma Quadrant. A group of renegade Jem'Hadar seized the gateway for themselves and re-activated it using equipment stolen from Deep Space 9. It was believed that they intended to use the gateway to foment an insurrection and mount a takeover of the Dominion. If they succeeded, the rogue Jem'Hadar would then gain the ability to move a force of any size onto any planet in the Federation or Dominion alike. Therefore, a joint Starfleet-Jem'Hadar team, led by Benjamin Sisko and Omet'iklan, successfully retook and destroyed the gateway. This second gateway generated some type of interference that prevented the functioning of energy weapons in its vicinity.
|Places seen through the Iconian gateway on Iconia|
|Places seen through the Vandros IV gateway|
In the alternative 25th-century timeline of Star Trek Online, gateways formed the core of the galaxy-spanning Iconian empire, connecting the Iconians' various worlds and the species they enslaved. Gateways were located in all manner of places, and in a variety of sizes, from the small personnel-sized ones seen in the show to ones large enough to admit entire fleets of starships. Some were experimented upon by the Tal'Shiar, who have aligned themselves with the Iconians.
During the mission "Sphere of Influence", player characters attend the test opening of a gateway discovered on New Romulus, the new homeworld of the Romulan Republic located in the Tau Dewa sector, and the ancient home of the Dewans, an Iconian servitor race. The gateway activates and players are transported alongside Worf to a facility located in Subspace and managed by the Solanae, a type of Solanagen-based lifeform and another Iconian servitor race.
Attempting to get home, players accidentally trigger the entire gateway network, reactivating dozens, if not hundreds of Iconian gateways scattered throughout the galaxy and triggering incursions by the Elachi (also known as Shroomies). After fighting the invasion, one space-based gateway is found to lead into a Dyson sphere located in the Delta Quadrant.