(covers information from several alternate timelines)
The Communications Research Center was a Starfleet Communications research and development facility for advanced communications technology. This building was a part of the Starfleet Command complex in San Francisco on Earth. The center included several holodecks.
During the late 2370s, it was home to the Pathfinder Project. As of 2377 its staff included Admiral Owen Paris, Commander Pete Harkins, and Lieutenant Reginald Barclay. (VOY: "Pathfinder", "Inside Man", "Endgame")
The Communications building is a modified picture of the Bank of China Tower in Hong Kong.
In VOY: "Endgame", the building is seen to occupy the location where One Maritime Plaza presently stands. Curiously, the Embarcadero Freeway, which was demolished after the Loma Prieta Earthquake in 1989, can be glimpsed in the upper left hand corner.
The interior of the Pathfinder Project lab and conference area was designed by Tim Earls. It intentionally used concrete and stone to differentiate it as being within a ground-based building, rather than a starship or space station. Early concept art included exterior windows in the lab. (Star Trek: The Magazine Volume 1, Issue 24, p. 31)