Does anybody have an 840sx networked through ethernet sharing sonar with another unit. Manual is vague. Emailed customer service snd asked if it was possible. They told me if I wanted to network sonar don!t buy a 840sx (?). Got a great buy but Garmin is 0 for 2 so far ( I haven't opened the box yet) and thinking there might be a better choice. This is silly not asking much.