Hi I am trying to provide socket for a SH 300i Plotter in cockpit as well as at the chart table, and also interface the SH 1500 DSC VHF at the same time. I thought it would be a good idea to use a 8 pin Bulgin Micro waterproof plug and socket termination at the plotter cable end, and the corresponding sockets at the two locations. I can form a junction in a small plastic enclosure box, with choc block connectors, within the fuse board which will allow me to join into the NMEA side and also form a supply termination as well , I could then use the whole connections later if I decided on the need for A.I.S etc.
There is ST60 Wind, and Tri Data in the cockpit, and a Multi at the chart table, along with a Garmin 128 supplying the GPS input , the whole lot linked by Sea Talk I assume, but I not sure how, or even if, I could tap into them, so decided to try and do it separately.

I wondered what spec cable I need. I did think I might use 8 core alarm cable with tinned cores, with a rating of 1 amp per core?

Would that be sufficient amp rating to carry the power supply side as I am not sure just how much the plotter needs?

Does that all sound feasible?

Would the alarm cable transfer data ok? Or does it have to be a special data specification cable, and if so what is the spec needed please?

Final question, while on the subject of the SH300i I have a warning sign in the Chart Display at the top right-hand side, of a red bordered yellow triangle with a black exclamation mark in it. Does anybody know what this is to imply? I have read the original and updated manual from cover to cover and found no reference to it anywhere?

Could it be something to do with the boat being on the berth and stationary?

Sorry this post is so long, and as usual will be most grateful for any advice