CallUp Missed Call Alert (MCA), also known as 'Who Called Service', provides mobile subscriber´s with notification regarding all unsuccessful incoming call attempts ─ including calls that did not terminate in the deposit of a voice mail message and calls that were made when the mobile handset was not in service ("empty" calls).

Who Called benefits both operators and subscribers by providing an attractive business opportunity and an enhanced subscriber experience.

Calls are "lost" due to the following reasons:
• The caller does not wish to leave a message (slam down)
• The subscriber does not have a Voice Mail account
• The subscriber has a Voice Mail account but it is unavailable
• The mobile handset is not in service

Who Called provides a complimentary service to Voice Mail and enables the mobile subscriber to receive notification of all calls that were directed to the Who Called platform including subscribers that do not have Voice Mail accounts.

Subscribers that choose not to have a Voice Mail account will receive notification of all incoming calls with no obligation to call back the calling party.

All calls that are directed to the Callup VAS Platform will be saved by Who Called regardless of whether the subscriber´s mobile handset was in service.

This service eliminates missed calls and generates additional air-time for the Operator when the subscriber calls back the calling party.