Originally Posted by
Tx Champ
The red & black wires are all that power any of the units and they are the same on all the blue connector power cables. The other wires are for other options, NMEA2K, NMEA 0183, RS232 & RS422. The HDS cannot power the NMEA2K network so it has to be powered through the power cable or a head unit that will power the network. The issue there is that if the unit capable of powering the N2K network is on the bow, it has to be powered on for the network to work. That's why it is recommended to power the network via a N2K-PWR-RD power cable connected to a T in the backbone. I power the N2K network via the A1 switch on the MegaLink system that also powers the HDS units at the console and the bow. My original StructureScan module and dash mounted LMS-520c are powered through the A2 switch.
Both of my HDS units are powered with the original power cables that were in my boat when I got it. A X-135 in the dash and a LCX-28c on the bow.