Sam,
Your instructions are very helpful. I just got an old Western Electric KTU working using the 1st line key, with the light working as well. What are the pairs for the other line keys on these old 1A2-style KTUs?
I don't suppose the ringing would work for any but one line to be wired at a time, without using a KSU, as all lines would need to be jumpered together to the YL/SL pair in order to ring.
Anyway, I just wanted to say thanks for the helpful instructions!
