sending AT commands to baseband on 3GS

Hi,
I'm trying to send AT commands to the baseband using the previously working method: using minicom 2.2-3 on /dev/tty.debug at 115200bps/8N1
I'm on a brand new 3GS: the baseband doesn't respond.
Did someone already reached to make it running on a 3GS?
Did something change between 3G and 3GS?

I just used it the other day to figure out the Baseband bootloader version on my 3GS and everything seems to be working fine for me. I installed the latest version from cydia. Not sure what version.

Thanks for this info, I've reinstalled my iPhone from scratch and now I'm able to send commands using ssh and MobileTerminal.
The main issue was that it takes some time to be able to send the first AT command and receive OK, so I have to be patient...