The Free On-line Dictionary of Computing (19 January 2023):

Communication and Network Riser
CNR

    (CNR) A specification for audio,
   modem, USB and Local Area Networking interfaces of core
   computer logic chip sets.  Intel introduced CNR on
   2000-02-07.  It was mainly developed by hardware and software
   developers who helped release AMR (Audio/Modem Riser) and is
   used by several computer manufacturers.

   (http://www.computerhope.com/jargon/c/cnr.htm).

   (2007-03-15)