We use both Moxa and Quatech wireless devices. They both work with the correct software, but not all DNC software can properly handshake through the device drivers for these units. Both provide device drivers that give you a "logical" COM port for your software, but some software is limited to using COM1 through COM4 (old DOS programs) and can't access the higher COM port numbers that the wireless units may assign.
If your DNC software does the Xon/Xoff handshaking "internally", then you'll probably have trouble with buffer overflows on the Fanuc controls. If your DNC software uses the device drivers in the Moxa or Quatech units, then you will probably not have trouble. If you use Quatech SSEW-100D units, be sure to hit the Quatech's web page and set the serial port to "Low Latency" so the handshaking is better. On the Moxa NPort 2150 units, set the serial port to "Classic mode" and turn off the FIFO buffer. Buffer overflow alarms on the Fanucs usually mean that the DNC software is not handshaking fast enough.
You can find the Moxa and the Quatech units online from several distributors. Also, having a good Access point is critical. We use DLink access points, although others will work.
Of course, if you need to hire a professional ... Contact my buddy John at Refresh Your Memory, Inc. firstname.lastname@example.org We install a lot of wired and wireless DNC systems, and we could ship you a couple of wireless units and the software on a trial basis.