Is the SMA SB RS 485-N Communication Card RS-458 Module (485USPB-NR) Piggy Back compatible with Sunny Island Inverters? Posted by Frank Molina, Stellavolta on Apr 17th 2020 Yes, the SMA RS 485-N (485USPB-NR) is compatible with boy Sunny Boys and Sunny Islands. Here is an SMA link to an informative video by SMA on how to use the card. Piggy Back Card SMA Sunny Boy Sunny Island