Sea Talk Configuation

I have installed a Fusion AV 750 sound system which has a NEMA 2000 connection and compatible with remote control from my c97 MFD.

I have a SeaTalk backbone installed with all three white connections connected to different devices. (A06064) I also have a conversion cable (A06045) to convert NEMA 2000 cable from the AV 750 to SeaTalk.

How and what components do I need to add another connection to the SeaTalk network backbone?

Thank you.