The Telit GM862 is a self-contained communication processor with integrated RF hardware running it's own GSM protocol stack. One side of the module is connected to an application processor (like the GumStix PXA270) and an audio path and the other is attached to a suitable antenna. The module does everything in-between.
The SqueakyMoPho Project (now a bit moribund) has a little more information about working with these modules (specifically how to get the SparkFun carrier boards to work with Macintoshes) and pointers to documentation which are repeated here. The module comes in several models, including one with an integrated Python interpreter and another with GPS hardware.
- GM862 QUAD PY Product Datasheet
- GM862 QUAD PY Product Overview
- GM862 Hardware User's Guide
- GM862 Software User's Guide
- GM862 AT Command Set Guide
For the Franken-Phone, I used the GSM USB Eval Board from SparkFun. They also have an [RS232 eval board] for those of you with real 9-pin serial ports out the back of your machines. USB Eval board users will be interested in these docs and drivers:
As a Mac user, I was a little disappointed to discover that I couldn't find Mac drivers where the "Installing USB Drivers for the 210X" document indicated. But I was able to find some 210X drivers at the Chip-45 site.