US Patent 7366535 Push-to-talk mobile communication terminals

Mobile communication terminals comprising a processor unit, a microphone, and a sound processing module for processing sounds captured by the microphone. The processor unit is configured to operate the terminal for a push-to-talk communication with at least one other mobile communication terminal via the communication network, and to operate the terminal during said push-to-talk communication in a latency state or in an active state in which sound captured by the microphone is processed by the sound processing module and sent to the at least one other mobile communication terminal. The processor unit is also configured to change from the latency state to the active state in dependence of the sound captured by the microphone.