Starfleet Communications
From FEInfobase
Starfleet Communications is a division based in New York city on Earth tasked with the responsibilities in maintaining communications with all Starfleet starships and space stations. Starfleet Communications is commanded by Captain Reginald Barclay.
Currently it is tasked with rebuilding the vast sub space communication relay the Federation had in place before the start of the Borg War. It is also responsible in re-establishing contact with lost ships and starbases. See Pathfinder Project.