Call keeper is the solution for subscriber to provide SMS notification to the caller for information that the destination number is now available or can reached, so subscriber can try to make a call again.

For example: When we make a call to a friend but at that time they are not available or cannot be reach, and then we will receive an announcement or go to their mailbox. But when will we know that he/she can be reach again? For that reason we need a service that can give an alert or notification that make us know if the subscriber is available to call or reach.