In 1998 I used a Siemens M1 for seven months but I had to give back its owner. Nowadays I have no GSM device to try out new program versions. However I got some feedback, that there are serious incompatibilities between various GSM devices as well as firmware errors in them. So I started to improve samsem package in order to be more flexible. It knows about detailed features of different devices as Siemens M1/A1/M20, Falcom A1/A2, Nokia Cardphone/Datacard etc. Samsem and samsemd will try to recognize the actual device and adapt themselfes to the hardware.
The current version is 4.3 alpha.
Unfortunately while I have no testbed I cannot guarantee that the new programs work well.
If you have any GSM module and a *nix machine on the Net you can help the development. Please give me a temporary account on your machine and allow me to debug Samsem on it.
Don't worry. It won't be expensive for you because I don't want to send any messages. ;-) I would just test automatic device recognition and PDU encoding.