The RT6-1000 app uses NFC to communicate with various Sonardyne acoustic positioning devices, primarily the RT6-1000 acoustic release transponder.
These transponders are typically attached to frames hosting underwater monitoring equipment (such as doppler profilers), to allow recovery of the frames at the end of a deployment.
NFC commands initiate acoustic messages to be sent through water, which action a mechanism that releases buoys attached to a rope.

The app uses NFC commands to initiate acoustic ranging between the products. Location data is required so these ranges can be geo-tagged, allowing a user to derive a real-world position of the seabed target.