LED Cube XBee slot on bottom?

Hello,

The LED cube has an XBee slot on the bottom. Has anyone used the slot?

It looks like it is all set up to let a 3.3v device talk to the 5V Rainboduino. The schematics say that the slot is only connected to a connector on the main cube board. Is the idea that you could then jumper the tx and rx wires to the rainboduio rx/tx lines?

Thanks

joe.blog.freemansoft.com/2011/05 … e-and.html