The shoreline cord connects your RV distribution center to power. Older models have a J Box, which has a receptacle coming from the generator and another that goes to the distribution center. This requires you to have to go outside and plug in the generator every time you want to use it. Newer models come with an automatic RV transfer switch already installed. It is possible to upgrade older models to an automatic 30-Amp RV transfer switch to put everything in a single box.