Determine the amortization component for a fiber rate based
on 15 year life cycle for a fiber strand.  

Conduit distance from Comm Bldg to Music Center is 8000 ft.
Construction cost for underground duct is $100/ft.
A fiber cable with the same strand count (48) presently
installed is about $2 per foot or about $25,000 installed
with connectors and testing.

The annual cost per strand is $1145.

Most of the money is in the duct.  You could reasonably
hope for a life cycle period of physical facilities that
is longer than 15 years.  

There are other components to a rate, for example, if you
want someone to answer the phone when someone calls with
a problem.  This is just the amortization piece.