NFC Near field communication

According to NXP, the Nexus S will ship with its NFC chip configured to only act as a reader. You'll be able to scan tags in public places just as you would with QR code, viewing the associated data on your phone. That's only scratching the surface of what NFC offers, though, as using the phone's chip to also transmit data opens the door for proximity-based payment systems.






NFC (Near Field Communication) is a communication device operating at 13.56 MHz jointly developed by NXP Semiconductors (formerly Philips Semiconductors) and Sony Corporation for use over short distances. It has been accredited as a second generation standard for RFID technology (Smart Card / RFID Tag) by International Organization for Standardization. It is expected to be used widely in various electronic devices in the near future.
NFC is compatible with the Sony developed “FeliCa™,” a Smart card that is widely used in Japan and in parts of Asia, and with the Philips developed “Mifare®” which is used in internationally accredited standard (ISO14443 Type A) and which is the most popular Smart card in the world. It is also able to communicate (read / write) with these products. Further, since NFC modules could communicate with each other, it is expected that NFC would be used more flexibly and in broader range of applications than the conventional Smart cards.

FC wireless communication is limited to within a maximum communication distance of approximately 10 cm. However, rather than treating this as a technological constraint, it is better to consider this limitation in communication distance as one way to prevent unauthorized readouts.



 more about NFC:
http://www.nfc-world.com/en/about/function/

Phone Nexus S 
http://pocketnow.com/android/nexus-s-nfc-read-only-for-now-full-support-coming-later