It seems redundant to suggest that one read the manual first, but hardly anyone does. I confess, I once hooked up a Sonic Hub, Navico’s integrated sound system, into my multifunction display, and it wouldn’t play. I even called customer service, and a representative walked me through the process of activating the MP3 player. The problem was that it had defaulted to a microphone input upon installation — the icon was clearly visible in the status bar, but I didn’t know what it meant. The process was clearly explained in the manual. I was clearly embarrassed.