The NetX does too attach to the network -- exclusively. It will not/can not use non-802.11 RF to communicate. Each NetX has a small 802.11 wireless NIC chipset inside, and communicates over your existing LAN setup using 802.11b. As such, the NetX must be in range of at least one of your wireless access points to work. There is a reason the NetX is configured with an IP address. :)
I have 3 NetX's (in different locations) in use here in my home alone, and they are all working famously. I did have to add a booster to one of my access points, and had to put in an additional access point elsewhere, to extend out my coverage so it would encompass the NetX.