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

unshielded twisted pair
UTP

    (UTP) Normal telephone wire (in the USA).  It may
   be used for computer to computer communications, e.g. using a
   version of Ethernet or localtalk.  It is much cheaper than
   standard "full-spec" Ethernet cable.  It comes in five
   "catagories":

    cat.   wires   transmission
    1	two	voice no data (telephone cable)
    2	four 	data up to 4 Mbps
    3	four	data up to 10 Mbps
    4	four	data up to 16 Mbps
    5	four	data up to 100 Mbps

   (2003-07-04)