It uses bluetooth. We don't offer one, but an Internet search did produce some results. It will have to be one that connects to power and works wirelessly, no inputs like USB or the like.
Here is one I found. *****Disclaimer***** I have not verified this unit just pointing out it seems robust and only requires a power connection.
Yep, I see where your going. I was thinking along those lines as well. I'm trying to figure out how I would pair the two devices or if the extender would even recognize the furuno bluetooth signal?