Xbee on fezmini robot kit

FEZ Mini provides pins with RS232 level.
What is it the voltage ? (The voltage of the rs232 is it +/- 12v ?)
How is it possible if fezmini is powered by 5v (usb)

Another question, on fezmini/robot there is a rs232 connector,
if I want to connect an xbee module, can I connect to it ?
xbee I think that requires 3.3v of power supply and signal.
If I connet it on the fezmini rs232 pin what happens ?
What the level on fezmini rs232 pin ? I need a converter ?

If instead use the pin: com2(UEXT3/UEXT4) , com3(di7/di8)
should work fine because they are normal uart ?

Thanks stefano.

FEZ Mini steals the negative voltage from the incoming signal. Positive is 3.3V which is still within the RS232 limits. Take a look at schematics for details.

Yes you need to use another UART with TTL levels to connect your xbee.