BlackVue coaxial cables are to be used to connect the second, or third camera to the front camera. They are only compatible with the 2Ch, or 3Ch camera options. These cables are compatible with:
DR590X-2Ch, DR750X-2Ch, DR750X-3Ch, DR900X-2Ch.
These are not compatible with the DR590/DR590W Series and DRS series.
All of these BlackVue dashcams use the BlackVue Analog Video Cable instead.