In the Babylon 5
universe, large, fixed spaceborne structures that are used to generate jump points
for ships that cannot create them unaided.
The first jumpgates were constructed long ago by an unknown race; races such as the Centauri&and the Minbari learned how to operate them, and later were able to build their own. They then passed this technology on to other races.
Jumpgate construction requires the mineral Quantium-40.