Dual-interface NFC tags to bridge smart devices

March 14, 2013 // By Graham Prophet
Inside Secure has introduced a near field communication (NFC) tag to increase options for interaction between NFC mobile devices such as smartphones and a broad range of medical, communications, entertainment and other electronic devices.

In addition to a conventional NFC contactless interface, the new Inside dual-interface, NFC Forum Type 4, tag also provides a one-wire interface that allows the tag to provide a low-cost wireless communications bridge between two devices, opening the door to an array of new NFC applications. The addition of the one-wire interface to the NFC type 4 tags, turns basic storage devices into a versatile communication channel that can be a very cost effective alternative to Bluetooth or other connectivity technologies, the company says.

For example, a single tap of an NFC phone to a Bluetooth wireless headset containing one of these tags can initiate the pairing operation. The tag detects the NFC field on the contactless interface and sends a pulse over the one-wire interface to the controller inside the headset to start the pairing process.

You could use the same kind of field sensing to quickly and automatically establish Wi-Fi connectivity for the first time between an NFC device, such as a tablet, and a new wireless access point, or to start transferring data, through the tag, between the NFC and host devices.

The dual-interface NFC Type 4 Tag comes in two memory configurations. The VaultIC 151D offers a 1.5-kByte file system size, while the VaultIC 161D has a 16-kByte file system size, the largest in the industry. Each tag integrates a standard contactless interface with full ISO14443 Type B protocol support for communicating with NFC devices and an Inside Secure proprietary one-wire interface for connection to a host processor (using just one GPIO). Accessing the data contained within the file systems from either interface is performed using the standard NFC Forum command set.

The large 16-kByte storage capability of an embedded VaultIC 161D NFC tag makes it suitable for use in home medical monitoring devices, where it is able to store a day’s worth of medical data from the device’s host processor through the one-wire interface. At