The SIEMENS TC35 is a standard AT commands Based GSM module, you can easily apply it with your own embedded system to creat a GSM wireless based data transfer module that supports Arduino!
The SIEMENS TC35 Module is an AT Command - controlled gsm modem, via Serial Port (RS232/TTL communication). Program source code would be provided so that buyers can use the module easily and get familiar with the module quickly.
Common applications are (sending/receiving) SMS control, phone calling, etc.