I asked a high-level contact at Kastle about this, will post an update if they reply.
Spoke with someone at Kastle about this, they don't want to divulge too many technical details yet as some components of this are in the process of being patented.
There are apparently multiple patents (not sure how many) that are based on research and development that Kastle did, so it's not just an OEM.
It works off of BLE for both iPhone and Android phones. They didn't want to build it off NFC because Apple has not adopted NFC or given indications when/if they will.
They claim it is unique from other offerings because it is completely hands-free, and does not require a user to interact with their phone to open a door.
There are multiple customers that have been using it for several months now, it is actively deployed.
You most likely won't find a specsheet online any time soon. Kastle acts as an integrator and sells direct to their customers/users. In my experience they operate in selective areas, and work with customers to develop complete solutions vs. putting product catalogs or specs online. I think Kastle wants to keep this product as a competitive advantage and not provide extensive details online.
I just found this link from appleibeacons.com (link) that has SSN's article reposted. I'm 99% sure that KastlePresence is using iBeacons. For anyone to get this technology, you just need to follow Apple's Developer guidelines when creating the app for the iPhone and Cross Platform guidelines for Android and Windows phones. Not sure why you would need to hire 20 Engineers for this as the foundation is already laid by Apple and a few other companies. I've been wondering when someone in the security world would try this. This is something many integrators and manufacturers could do. Truthfully, I'm not sure at how well this would work for Access Control as it has the same physical fault as NFC Card Access.
I wonder if you install the beacons if you will also get future advertising dollars, as the beacons could also be used to track peoples locations and send them phone messages with a deal and etc., which is why iBeacons were created in the first place.
What is iBeacon Technology link
Apple's iBeacon for Developers website