Phone Wire Colors:

In the days of old, phone wires used solid colors. Your primary phone
line would be on the green and red wires. If you had a second line, that
would be on the black and yellow wires. The red and yellow wires were
the Ring wires, and the green and black wires were the Tip wires.

However, times change, and so do wire color standards. There is a new
breed of telephone wire, which uses multi-colored wires which are
banded with white and some other color. The new standard for wiring is:
Line 1 Blue, Line 2 Orange, Line 3 Green, Line 4 Brown. On all of
these pairs, one wire will have thick white bands and thin color bands,
and the other wire will be vice-versa, thick color bands and thin white
bands. The wire with the thick white bands is always the Tip wire, and
the wire with the thick color bands is always the Ring wire.