As far as I’m aware, there are two types of instruments, the old fashioned ones which indiviual senders wired directly to their own display unit and the modern ones that use a Can-bus system where the senders and display units are all wired into the same circuit rather like, for example, the depth, speed, wind and autopilot on a Raymarine Seatalk system. The old and new type instruments are not compatible and will not work together on the same circuitry. I know because I have a great set of new Can-bus instruments bought with good intention but which will not work with my MD2020 D individually wired engine sensors.