It will work standalone without the RFX9400 or RFX9600 as long as you have the 9600 configured as a device on your wireless network (I suggest DHCP). Then, simply set the IP or Host name of your E2 on the Escient Device Properties.

However, your E2 must be running firmware version 4.1.7.XXX (whatever the latest is) that supports the Escient External Control Protocol as outlined in the PDF document available for download from the Escient Site.