In the USA (and Canada at least), 3 pair twisted pair cable is usually installed.
(as opposed to the 2 pair non-TP wire, called
JKT, distinguished by the red/green/yellow/black conductors)
Astute (usually after market installers) will install Cat5 wire for telephone.
Around here anyway, there is a slightly heavier
JKT with 3 conductors, and in an older house, I have come across an old 3 wire twisted cable, with brown insulation, with red/green/yellow silk strands in the wires.
The NIDs around here have just bolt terminals where the interior wiring connects.
