If you worked for the phone company long enough ago, don't forget the White/Slate, Slate/White. I cannot even begin to guess how many miles of 25 pair cable is still winding through office buildings. Viva le 5 button A1 desk sets !Just remember: It's white/orange, orange/white, white/green, blue/white, white/blue, green/white, white/brown, brown/white.