This tiny module will allow you to connect your embedded device anywhere in the world where cell phones are used. This version (GM862-QUAD) is compatible with the various 850/900/1800/1900MHz frequencies of cellular networks across the globe.
You will need to provide a SIM card. Pull the SIM card from your phone, insert it into the module, and viola, you are making calls under your cellular account. Works with all providers currently supporting SIM cards (AT&T, T-Mobile, and Cingular).
The GM862 module is controlled via AT commands. This means all you have to do is send a string of serial characters such as "ATD 3035551234" and the module will place a call. No fuss, no mess. Once the module has connected to another module or modem, a serial connection is made and data can be transferred as simply as passing and receiving serial strings through the module.
Note: This module does not support Python and is firmware version: PS:5.02.203/AL:6.04.204-GM862 QUAD. This is an older revision of the hardware, but it should work just fine for most of the normal AT commands. It does not support the newer, Easy GPRS commands.