I'm selling my current units and looking to get the 859 and 899. And want to link them together. Does anybody know what cables I need to do this? Ethernet and adapters. I have the terrova with universal transducer. But I want the 859 di. Is there a transducr that fits in my terrova. Or do I have to wire it separate? And if I need to do this is there an easy way to do it. Looks kind of tricky the way the terrova slides. Makes running wires tough. Also i read of another more durable transducer I can exchange that is more durable. Any help on this is appreciated. Thanks guys