Personal electronic devices, like smartphones, tablets, and laptops, are equipped with an increasingly wide array of sensors and effectors, including, respectively, microphones and audio outputs (e.g., speakers).
Ever since the introduction of cell phones, users have had to contend with their inadvertent use, such as a phone initiating a call simply because of its location in a user's pocket, when the user is engaged in some activity unrelated to the placing of a phone call.
More recently, with the introduction of smartphones, “hacking” (or unauthorized entry) into one of these devices is becoming an increasingly severe problem (since such phones have become, essentially, pocket-sized general-purpose computer systems, that also offer an ability to make phone calls).
Even where an application service provider's (“ASP's”) use of a device has technically been legally authorized by its user (e.g., through a “click-through” license), ASP's are increasingly using such personal electronic devices (and, in particular, the device's sensors) for purposes of which the user is not necessarily aware.
For example, companies such as FACEBOOK (Menlo Park, Calif.) and GOOGLE (Mountain View, Calif.) are able to track a user's Internet search behavior across multiple devices.
This cross-device tracking can be accomplished by causing first and second personal electronic devices to operate as, respectively, an audio modem transmitter and audio modem receiver. The audio transmissions are typically ultrasonic, and therefore inaudible to humans. The cross-device tracking can be used for such purposes as ad tracking, ad targeting, and for other user-profiling purposes.
It would therefore be desirable to give users a reliable way of disabling a personal electronic device's audio, so that privacy can be maintained, and unauthorized or unknown uses can be prevented.