jdo1942: I had to do the relay thing to add a second doorbell at the G/F's parents place. Turns out the transformer was large enough ( VA wise) to drive both chimes BUT the original bells were wired with 22/4 phone wire and would not operate properly when an additional chime was connected... Added a relay and rewired the button and existing chime ( with the existing 22/4 phone wire) and added in the extra chime and the problem was solved.
