US Patent 7966029 Method for push-to-talk pre-emption

Push-to-talk private call pre-emption may be applied in an application-to-person context or on a person-to-person context. A PTT subscriber may send a PTT server a pre-emption request indicating a desire to interrupt the application voice stream or another PTT subscriber, respectively. In an application-to-person context, the PTT server may revoke the floor from the application server and grant the floor to the requesting device. In a person-to-person context, the PTT server may send the other PTT subscriber a floor release request. Once the subscriber with the PTT floor releases it in response to the floor release request, the PTT server will be able to send an open floor signal back to the requesting subscriber.