Yes, in Building 5. There was also a long length of thick coax down
the hill to the main complex -- it wasn't easy to get nice, standard
fiber in 1982 -- that was the original Murray Hill backbone. Yes, coax
between widely-separated buildings -- great for ground loops.... That
was the first link in what came to be known as the "wet backbone" --
wet because the cage in the basement containing the repeaters was
occasionally flooded with fluids considerably nastier than water...
(We won't even discuss the time an electrician accidentally cut through
one of the legs of this (thick, yellow, coax) backbone, and decided to
splice it with wire nuts and electrical tape. This was cira 1989.)
--Steve Bellovin, http://www.research.att.com/~smb