Dumb question but I'm going to ask anyways because this is my first rig to have good electronics and I'm not up to speed with today's technology. I've got a Lowrance HDS 10 on bow and a HDS 12 at console. They are linked with ethernet cable. I've got a transducer on my trolling motor. If they are linked together, does that just link waypoints and GPS related features between the two? Or, will my bow unit actually read sonar off the transducer that my console unit is running on? I'm wanting to upgrade my bow unit to a HDS 12 so I'm wondering what all I need other than the graph itself?