Hi Giovanni, yesterday i spent my time trying to make e156b works under mod_gsmopen and finally got it working, e156b have a fucking issue that never AT +CREG works the way it should, it always returns 0 so i have to change all references to CREG o CGREG this way it will check GPRS status, and that works ok, i suppose the best way to have gsmopen working for this modem is to have a parameter to specify the AT command to check for registration (i didn't finish this functionality), for this to work, we have to make some changes because in your code you have a string comparison against with a fixed string lenght and not against the strlen function (strncmp(tech_pvt->line_array.result[i], "+CREG:", 6) ) so i can't easily change it to a string pointer, probably i will do next weekend. ( (strncmp(tech_pvt->line_array.result[i], string, strlen(string)) ) would be better.

Also the makefile must link against the debug libraries, if you follow mod_gsmopen instructions at the freeswitch webpage you will find a link error.