small footprint device for USSD/SMS

[João M. S. Silva]

Hi,

Sorry about the newbie question:

Do you know of any modular device to run USSD sessions? And eventually 
SMS? Or GPRS?

By modular I mean not a USB dongle, but a smaller PCB which I can embed 
in my machine instead of plugin it, hanging outside.

Does modemmanager support USSD commands?

Or should I use other software? Or maybe I have to use AT commands 
directly without any other abstraction layer?

Thanks for any insights.

For the moment I've been using an HSPDA dongle with which I send SMS, 
but I'd like to embed this dongle inside the machine (in a PCB cape) and 
also support USSD sessions.

-- 
João M. S. Silva