V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

CDDI
       Copper Distributed Data Interface (FDDI, UTP)


The Free On-line Dictionary of Computing (30 December 2018):

Copper Distributed Data Interface
CDDI

   (CDDI) FDDI running over conventional copper cables.  A
   Cisco/Crescendo copyright term(?).  All FDDI
   connections, single-attached or dual-attached, can be
   either optical fibre or copper.

   (1994-12-14)