摘要 |
In a method of operating at least first and second electronic devices, the devices are each arranged to transmit and receive ultrasonic signals, e.g. to operate a touchless user interface. Both devices, or at least two of the devices, are synchronised to transmit said signals at substantially the same time. The devices may, for example, listen to each other's ultrasonic signals or use a WiFi network access point for synchronisation. |