I'd like to invite everyone to participate in the development of gsm-ussd!
The GitHub link:
Right now, it's completely usable - for me. Of course I tried to make gsm-ussd versatile and robust. But testing was only done with my Huawei E160 UMTS modem. If you own other UMTS hardware, I'd love to hear from you and your problems/successes with gsm-ussd!