No, they cannot be connected directly to each other. They are designed to be connected as devices via a spur cable to a Seatalkng/NMEA2000 network backbone. (Forgetting about B/T for the time being)
Both devices are powered by the network power. At the minimum you will one Raymarine SeaTalkng 5 way connector, a spur power cable, two spur cables going to each device and 2 backbone terminator connectors.
Recommend you do a search on ”Raymarine SeaTalkng network“.
This thread has a lot of good information on building a SeaTalkng network.
STng