A Type-XI phaser was a type of phaser emitter usually installed on Federation Starfleet space stations.
History[]
When Starfleet began upgrading Deep Space 9's defenses in preparation of a Dominion assault in the early 2370s, arrays of this type were installed in the station's defense sails, along with Type-IX phaser turrets. (DS9 reference: Star Trek: Deep Space Nine Technical Manual)