send message using gsm

ss=serial('COM7');

ss.baudrate=9600;

fopen(ss);

ss.Terminator = 'CR'

tx ='AT';

tx1=char(13);

tx2 ='AT+CMGF=1';

tx3 ='AT+CSCS="GSM"';

tx4 ='AT+CMGS="=[phone]"';

tx5 ='water';

tx6=char(26);

fprintf(ss,'%s',tx);

fprintf(ss,'%s',tx1);

pause(1);

fprintf(ss,'%s',tx2);

fprintf(ss,'%s',tx1);

pause(1);

fprintf(ss,'%s',tx3);

fprintf(ss,'%s',tx1);

pause(1);

fprintf(ss,'%s',tx4);

fprintf(ss,'%s',tx1);

pause(1);

fprintf(ss,'%s',tx5);

pause(1);

fprintf(ss,'%s',tx6);

[Van Basten]

which gsm module are you using?

im using sim900a in algeria bought from amazon.fr but it's not responding to any AT commands. any help?