I have a 28hd mounted in dash in my 619 . I am wanting to install another 28 on the transom.It looks as though I can tye into the t conector at the transom for the gps. I am hoping not to have to install another transducer. I am unsure as to how the two units would recive the sonar information. I am hoping this is not a difficult installation.

to share sonar all you need is a ethernet cable and link them between the two yellow plugs. this will share your sonar data.

to share you gps puck all you have to do is have the network set up properly with the correct t's and resistors and it works great!!!!

its a pretty simple system.... just like hooking up a tv....

i could be wrong, but i don't believe the ethernet cable shares the actual sonar, just the depth reading. but you could buy one of these http://www.lowrance.com/en/Products/Accessories/
they have been around a long time.

ehternet will share the sonar charts as it has the bandwidth to allow it

the nmea netrworking will only show depth readings etc

thats my understand of it at least