PLEASE, TEST FIRST IF IT WILL WORK FOR YOU BY USING THE COMPANION GPS PROTOCOLS APP - https://play.google.com/store/apps/details?id=com.michalbures.garmin.protocols
IF THE APP CAN'T CONNECT TO YOUR GPS please check with USB Device Info app (https://play.google.com/store/apps/details?id=aws.apps.usbDeviceEnumerator) if your Android device can see the GPS connected. If yes, then please send contents of the app log (top right menu button) to email@example.com, so I can try to figure out what is the problem.
GPS Transfer allows you to transfer tracks, routes and waypoints between your Garmin GPS and your Android device.
GPS Transfers supports both Ozi Explorer's formats (waypoint (.wpt) and track file (.plt)) and the GPX format.
To find out if GPS Transfer is compatible with your devices please use the companion app GPS Protocols - https://play.google.com/store/apps/details?id=com.michalbures.garmin.protocols
You can also use USB Device Info app (https://play.google.com/store/apps/details?id=aws.apps.usbDeviceEnumerator) to check if your Android device can see the connected GPS.
For further information see http://bures.io/products/android/gps-transfer/
Write to external storage:
In order to save data from GPS to a folder of your choosing