-T indicates "twisted pair". Vampire tap was 10BASE5 (later also called Thick-Ethernet, to contrast with 10Base2 "Thinnet" which used thinner coax and BNC T-pieces)
I never saw 10base5 coax, but I worked in a lab in the day with massive thick 15 pin cables everywhere (AUI?), and 4 port hubs (that is combine 4 computers into one uplink that I supposed eventually went to coax in the ceiling, though I only saw it go to yet another such hub. The office was 10baseT already, but the lab had a lot of older computers.
10BASE-T and 100BASE-T require 2 wires to transmit and 2 wires to receive, 4 wires total. Actually it is better to call them 2 pairs since it's a balanced arrangement in which each pair signals come and go in reverse phase from the interface transformers and wires of each pair are twisted together so that any picked up noise can be canceled out.
1000BASE-T (Gigabit Ethernet) uses all four pairs, that is, all eight wires of a CATx cable.
And, as a earlier poster explained, there is 10GBASE-T1,
which is 10G over a single pair! Wow! Who knew!?
"The 88Q4364 is manufactured using a standard digital CMOS
process and contains all the active circuitry required to
implement the physical layer functions to transmit and receive
data on a single balanced twisted pair."
I'm not old enough to have liven when 10BASE-T was mainstream.