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

RJ45
       Registered Jack 45 (cable)


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

RJ-45

    A serial connector which looks very much like a
   standard telephone connector, except it houses eight wires
   instead of four.

   RJ-45s are typically found on computers either integrated
   into the mother board or on a NIC.  Because they are so
   small they are often used on devices such as terminal
   servers that have many ports.

   Ethernet (10baseT) and Token Ring sometimes use four
   wires of an RJ-45 plug, 100baseVG uses all eight.
   100BaseTX uses the same four wires of the RJ-45 connector as
   10baseT but the wire must be category 5 instead of category
   3.

   [Would the cable normally be shielded twisted pair or
   unshielded twisted pair?]

   (2004-05-22)