I have a 998 si at the console and an 898 si on the bow, i have one GPS antenna at the console. both are hooked with an Ethernet cable. if you have more than 2 units to be able to talk you need to get the Ethernet hub. but 2 units dont need the hub.my 2 units are configured to use the 1 gps antenna so if i wave point on one i can see it on the other. once the Ethernet is connected you have to enable it on the units, when this is done you will get a new tab on the units and can select which transducer to use, temp and gps antenna. very easy to set up. the screen views and map chip data are the only thing that are not shared.trpcollier:the 998c SI Combo CHO is the one that does not come with a transducer. this is where i got my units, best price i could find by far!!!http://moodeals.com/index…0e8794c1924ccdbc54edc002Last edited by socalpIII on May 14th, 2012, 10:08 pm, edited 2 times in total.