I have an 1198csi at the console. and I'm installing a 998csi at the bow. These are not the new HD units. I want to be able to share data IE Waypoints and my navionics chip between the 2 units. I also want to use both gps pucks.When I'm at the bow i want to use gps at the bow. When I'm idling around i want to use the one at the console.I only have one nav chip. Can i do this with an ethernet cable or do i need the interlink box?