UNICOM Electric 802.3af - Manual (Page 6)

System Power LED indicator
DIPswitch: The DIPswitch changes the splitter voltage allowing for it
to operate with a variety of products. It provides four voltage values –
5V, 7.5V, 9V and 12V. The default is 5V. Before adjusting the
DIPswitch, disconnect the power from Splitter Adapter.
DIPswitch