The Vexilar Sonarphone is a wireless transducer that gets its display via WiFi to a smartphone or tablet. There are three Sonarphone versions. One is a castable bobber transducer T100, and the other two are boat mounted with power supplied either by the boat T200 or its own battery T300. Only the boat mounted versions will do the mobile device pairing for Sonar Charts Live.
Navionics paired with Vexilar to have Sonar Charts Live on the mobile device. The system creates depth contours in real time that are written and stored in the mobile devices memory. Additionally when the device is in a WiFi area, that data is automatically uploaded to the Navionics server to be added to the Navionics Sonar Charts shared mapping after processing that can be viewed on their Web App, downloaded to a Navionics maps card with Sonar Charts capability, and is also added to the Navionics Mobile App maps.
The Sonar Charts Live sonar source can be via WiFi from a Lowrance unit, and a couple of other sonar unit brands. Still viewed and processed by the Navionics Mobile App.
I use the Vexilar Sonarphone/Navionics Sonar Charts Live setup.
I also use the Humminbird Lakemaster Auto Charts Live with my ONIX. The new Humminbird Helix models in the 9, 10, and 12 series have the built-in Auto Charts Live feature too.