extern int EncodePDUSMS(GSM_SMSMessage *SMS, char *frame);
extern GSM_Error DecodePDUSMS(unsigned char *message, GSM_SMSMessage *SMS, int MessageLength);
extern int EncodePDUSMS(GSM_SMSMessage *SMS, char *frame);
extern GSM_Error DecodePDUSMS(unsigned char *message, GSM_SMSMessage *SMS, int MessageLength);