I just got a call from this number as well 425-412-8510 1:49pm eastern time Tuesday April 28, 2015. Wanting to put a free security system in my home in exchange for a small sign place at the home. Not sure it is a scam or not, I just don't like people who use the worst 4 letter word I have ever heard 'FREE'.
I have received 2 calls from 2 different numbers the first guy hung up on me when I asked to be taken off the list. I called back and got another person and had him take me off of the calling list and he told me it takes 48 hours. It's hard top block the number when they use more than one....