kenberland wrote:(Except the backlight. Anyone know how to get that working???)
AT&T/Western Electric had two series of Trimline phones. The later series had LEDs in the dialpad to illuminate it, drawing the power from the line current. My Trimline phones were LED-illuminated.
The first series had a small incandescent bulb in the dialpad. It received its power from the second pair of wires, with a wall-wart transformer somewhere in the house near phone wiring. It sounds like you may have that version.
You can check whether a rotary Trimline is an LED model. If it is, it will have "LED" printed under the fingerstop (which moves when dialing, allowing you to see under it). I searched to see if there is a way to check if a Touch-Tone Trimline phone has something similar. I didn't find anything, but
on this page, I found this helpful information:
The first Trimline models used incandescent dial lights powered by a power transformer plugged into a standard 120VAC outlet. The bulky transformer and the need for a conveniently-placed 120-volt outlet was criticized by many consumers, but was necessary because of the power demands of the incandescent light bulb. Years later, Western Electric redesigned the Trimline to use a low-power green LED backlit dial powered by current from the phone line, eliminating the need for a separate transformer. Always eager to re-use its older stocks of turned-in rental phones, AT&T later repainted and sold early-model non-LED Trimlines as “non-lighted” models, without a transformer.