The one-ring-hang-ups are robodialers verifying that the number is assigned in a PSTN. If the number it's dialing is not assigned, the robodialer gets a "fast-busy". If the number is assigned, it rings through. They only need one ring to verify the number is active, so then they hang up. Prepare for the onslaught!
My caller ID said Numeris. Usually the scam artists block their business name, so I googled it and found this article http://www.theglobeandmail.com/arts/televisio ... article22838581
So they're legitimate, but why would you phone a person's house during the day when you'd expect that they'd be at work?
Got a call today, they didn't even ring for like 2 seconds before ending the call, was too fast to even answer, but the CID indicated "Numeris" as a name, investigating further shows it's some kind of "Canadian audience measurement" organization, but the number is suspect considering a lot of other people have heard of other things being who was on the other end of the call...