Can the Stargate transmit with GSM/CDMA?
Yes, this can be done. The Stargate is a Linux box, which can connect to a GPRS/CDMA network using a wireless modem card. One such card for CDMA is the Sierra Wireless AirCard 555. You will use AT commands to ask the card to make a data call, and then you will use pppd to setup a ppp link with the network. Check out the following page for how to use AirCard 555 with a Linux machine.
http://centerclick.org/aircard555/
Note that the instruction is for a specific card (AirCard 555) and for a specific carrier (Verizon in the US). You will need to adapt the procedures to the card and carrier in your region.