Typically you fill out the application so the NDA is agreed and they understand the project you are trying to accomplish. There is a lot of IP that isn't shared without NDA. If you e-mail them before filling out the required information, they are just going to normally send you back to the beginning. If you are in the USA the SDK e-mail is SDKsupport@furuno.com. If you are outside the USA responsible area, you would need to contact the responsible Furuno distributor in that respective area.