Addressable zone relay method and apparatus

An apparatus in a spatially distributed, multicomponent audio system uses an ultrasonic test signal for function assurance. The signal is detected in multiple signal routing devices within the audio system. Each device is equipped with a sensor that detects the test signal. A centralized polling station receives a test report from a device and generates a status report. The testing can be performed at scheduled intervals or by operator command. The results can be displayed graphically where the public address system supports this, and can include alerting processes in event of a fault.