you connect the 2 units together using the high speed data connection, via the nema 0183 protocol. the blue and brown wires need to be connected in a null modem config. the blue of one unit to the brown of the other unit and vice versa. then go into user data and select share user data ON BOTH UNITS.
the ethernet port is for panoptix transducer not for connecting 2 units together, although i believe the newest PLUS models may have enabled that function.
garmins work pretty well set as default out of the box, very simple and intuitive units.
that said, if you want to see fish clearly, set to 455mhz for sidevu and downvu(clearvu) the 800mhz setting shows great detail but the fish returns are weaker. if im looking for cover and structure i run the contrast at 50, when i find something that i like then i raise the contrast to 80 and lower the brightness. you can still see the cover but the fish returns will really pop out.
on 2d, i will run the sensitivity up until i start to see clutter and then turn it down until it disappears. you should have a clear 2d sonar.
as far as scroll speed for side image, leave it on auto. ive tried all of the settings and auto seems to be the best way to go. i always set the depth at the max depth i will be fishing.
side view i run at 60 ft max because a 7 or 9 inch screen really doesnt have enough pixels to be very useful past that range. if im scanning banks i will use a left or right scan only. this brings the scan to fill the while screen, ie, docks.
to map a waypoint, from say a brushpile on sidevu, DO NOT HIT MARK button (this marks the boat position). using the arrow keys move the cursor over the spot you want to map and hit the SELECT key.
a word on transducer mounting. keep the wires away from other wires especially trolling motor wires. if you have a variable speed TM they can cause interference with garmin units. on the transom, it needs to be mounted as horizontal as you can get it. i use a torpedo level, take the boat out and measure the angle as you are trolling both length and width(the boat will chocolate chip cookie to one side with only one person). i use a hand full of pennies under the level until its level at trolling speed. then back at the shop i raise the boat, with the level and pennies under it, until inget a level bubble. then i mount the transducer on the boat, check with a torpedo level to make sure its level and tighten down. what this does is make sure that transducer is perpindicular and level to the bottom at trolling speed for quality side images. use a transducer mounting board so that you can move it left or right if need be.
