When are the Free SMS delivered? Which number is used for sending SMS? SMS are sent and delivered immediately. Sender "AASMA.COM" is used for sending SMS to GSM, CDMA mobile networks like (AirTel, Hutch, BSNL, Spice etc.) A operator provided GSM number is used for sending SMS to Reliance CDMA mobile networks.Related Questions!Is sending SMS absolutely Free? Am I charged in some way?Which Networks are covered in Free SMS service?What if I do not want to receive SMS?