As I understand NFC offers three modes of operations :
Reading/Writing of/to NFC tags. (Coupons, SmartPoster tags)
Virtual cards are stored in Secure Element (PayWave, PayPass).
Communication between two NFC enabled active devices used in contactless services ticketing, money transfers or lower security access control applications
more: About NFC
Is it possible to combine these modes, and have NFC transactions between two phones, one as an emulated card in a secure element and the second as the reader POS? all informations about the subject is appreciated
Thank you.
Yes, what you are after is possible. What you refer to as card emulation mode, is commonly associated with the term digital wallet. In this case, the phone behaves like an EMV enabled payment card and transmits the necessary signals using the phone's NFC hardware.
On the other end of the spectrum is a reader. This reader can be another phone, or can be a typical merchant terminal that you see in retail locations. As long as both parties implement the standards properly, the data exchange can occur.
The merchant terminals however typically have stronger range than the sensors found in phones, so a payment at a merchant terminal is a bit easier to execute. As new phones come out, they tend to have better NFC antennas embedded in them however (for example comparing Nexus S with S4), so hopefully this gap will close. The EMV standards dictate a 5cm range for a reader to be compliant, though I've stumbled across many readers that don't have that range.
As you have guessed probably, I'm familiar with this space. I'm a cofounder of Triangle.io and what we do is to allow you to use any Android device as a reader for free. You can learn more about our API at http://www.triangle.io if interested. To go back to the question on hand, you can use one phone in card emulation mode, and on the other, you can use our API to read the other phone's emulated card. The phone emulating the card needs to implement the EMV specifications properly.