Raymarine SeaTalkHS Crossover CouplerRaymarine SeaTalkHS Crossover Coupler Engineered for the marine environment, the SeaTalk hs Crossover coupler provides a secure connection between any 2 SeaTalk hs devices. This device is commonly fitted on networks consisting of a single E Series display with DSM300, or 2 E Series displays with no DSM300. For networks with 3 to 8 devices, please choose the SeaTalk hs Network Switch.