Module firmware update

I have some modules Rev-B having firmware. Since the latest firmware 1.0.A.5 has got AES encryption feature, which is tempting for me, I would like to update those modules.
My question is how to connect the module to a PC (I have 3.3 level converter from Maxim) - what pins have to be connected? Is sufficient to connect VCC, GND, Rx, Tx pins as for normal operation?
I dont have any special development board.
I reckon X-CTU doesnt run under MS Vista, does it?

Cheers, Meereck

The X-CTU should run fine on Vista - although I believe there are certain versions or scenarios that might have problems (however, it runs perfectly on my home version of Vista).

To upgrade the module lines Vcc, GND, Din, Dout, RTS, DTR need to be connected. This schematic of a Digi interface board might be useful for you:

See the XBIB-R-DEV

Thanks for the unbelievable fast reply.
EDIT : I get it now.

Message was edited by: meereck

I try to change the firmware (change the version and after write) wihout the connections RTS and DTR and it’s ok? Do you know why you have to have these signals?
Thank you

To Read from and Write to the module (changing paramters) only the VCC GND TX and RX lines are necessary. To reflash the version of firmware on the modules, this also requires the DTR and RTS lines. In your reference design RTS is necessary from the serial port. DTR is simply held low during the firmware update. DTR is also the sleep pin, so if you aren’t using sleep on your module, DTR can simply be tied to GND.