A call control system for controlling testing in a mobile switching center (MSC) comprises an interface and a processing system. The interface is configured to receive a test call from a test device to a tone card internal to the MSC. The processing system is configured to determine a primary route for routing the test call to the tone card for a first duration, generate first routing instructions indicating the primary route, after the first duration determine a secondary route for routing the test call to the tone card during a second duration, and generate second routing instructions indicating the secondary route.