On July 23, 2010 at 00:11, vmail said...
What is the purpose of the Ethernet port on the RFX9400 in Use mode (position 1)
The extender can be connected to a Wired network and used in what is known as Network mode vs Standalone mode. Searches for "Network Mode" and "Standalone Mode" should provide more info. Also, you can refer to the manual that came with the Extender as this is discussed there as well.