XCTU Unable to Find Xbee Pro S1 modules

I have two new XBP24-AWI-001 modules. I have them bothe wired to FTDI ttl232 usb/serial adapter cables with a regulator providing 3.3V.
I have triple checked the connections and can see the signals at DIN on pin 3 with a scope as XCTU tries to find the modules.
What am I missing?