The Starfleet Communications Research Center in San Francisco was the facility that housed the Pathfinder Project, the team under Admiral Owen Paris working to contact the USS Voyager.
The centre is first seen in the sixth-season episode Pathfinder. Commander Pete Harkins runs its laboratory, where engineers model Voyager's probable position and test ways of sending a signal across the galaxy by way of the MIDAS array.
Reginald Barclay works there and spends his nights in a holodeck recreation of Voyager and its crew. Removed from the project, he returns after hours, sends a message through an artificial micro-wormhole and evades security inside his simulation until a reply comes through in front of the admiral.
The laboratory reappears in Inside Man and Author, Author, and in Endgame, where Barclay and Admiral Paris watch Voyager burst out of a Borg sphere near Earth.