Hummingbird 597 question

I currently have a 597 ci HD down image on my boat, is there another unit that is compatable with the wiring? I would like to put another Hummingbird on and use the existing wiring if possible. Thanks

First and second generation Helix 5 DI GPS, Helix 7 DI GPS, Helix 9 DI GPS, Helix 10 DI GPS, and Helix 12 DI GPS.