Xbee not recognised when wired to USB

I am very new to Xbee Modules so please forgive my ignorance.
I have two Xbee PRO S2B modules, also, I have an explorer which plugs directly to usb and another explorer which simply regulates 5v down to 3.3v and allows the xbee to sit on a breadboard. This explorer is made by parallax. Now my issue is that when the modules are plugged into the explorer which sits on the breadboard, they power up fine but connecting Din and Dout from the board directly to the green and white wires from the usb they are not detected by the computer. The modules work fine when using the other explorer but not when wired by myself. The explorer regulated these pins from 5v down to 3.3v but other than that I cannot understand how I am supposed to wire it in order to configure it on the computer.

Any advice would be greatly appreciated,



Matt, I would strongly recommend contacting the manufacture of the board you are working with as they will be the best one to answer that question.