The 1731mk3 uses a 24 pin connector on the display side of the scanner cable. You can order an entire connector kit (housing & pins) from your local Furuno dealer. The part # is AL1600CONN. If you need to locate a dealer, feel free to use our dealer locator on our web site. http://www.furunousa.com/Support/DealerLocator.aspx
Thanks for the input on installing the 1731 Mark 3. I was able to download the manual that has the detailed installation steps. Before I had the manual, I spoke with one of the Furuno engineers in MD who was very familiar with the unit and he stepped me through the process. Very knowledgeable and helpful.