Quote:
Yes the 520 runs on a red colored network cable. According to lowrance the only two gps (puck) that will work is the 2000 & 3000.
It’s on their compatibility list.
Source: http://www.lowrance.com/en-US/
Note;
LGC-4000 KEY FEATURES
When connected with HDS Gen2 models, it delivers a true satellite update rate of 5 times per second for the most accurate speed-over-ground readings. The LGC-4000 also features a new compact size that’s easier to flush-mount from the top. Rugged for all marine environments and fully waterproof, an optional spat cone is available for pole mounting.