Source : Free On-Line Dictionary of Computing

unshielded twisted pair
     
         (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)