SMS Callback
The SMS Callback Service allows GSM mobile phone users to initiate long-distance calls by sending a SMS (short message service) text message to GSM Modem/Gateway. The SMS message contains the destination number that the user wishes to call. Once the callback server receives the message, it SMS Call-Back service a callback to the user's mobile phone or to any other number specified by the user. Once the user answers, the callback server automatically dials the destination number and connects both calls together.
How it works:
A. Mobile user sends SMS to sms gateway.
B. Callback server receives SMS from sms gateway.
C. Callback server authorizes the user.
D. Callback server initiates a call to origination number through VoIP gateway.
E. Callback server initiates a call to destination number through VoIP gateway.
