the only reason i linked mine was so the waypoints would show up on both units, they both have to be on at the same time for this to work though. i simply ran an ethernet cable, i think with the 788 you have to have another connection to hook it to the ehternet cable i don't think it just screws in like the bigger units. i really don't think it is that big of a thing to link them, i mean its nice at times but not necessary.