They are trying to sell a "Wireless Home Security kit". You get it free in return for putting a small sign in your yard. There may be a $99 set up fee. He was very insistent that I give my name (I didn't) I asked him to give me the Company name so I could do an internet search but he kept asking for my name. I ended up having to hang up on him. IMHO, scam.
The same thing happened to me a few weeks ago. I told them I was not interested and seeing as I live in an industrial area with no yard to place their sign, their attempts are fruitless, they continue to call me. I suggest picking up and threatening to report them. Don't know if it will do any good, but worth a shot.