Abstract: Methods and systems for controlling the receipt and transmission of audio transmissions are provided. In one embodiment, a method is provided that includes selecting a first audio channel from among multiple audio transmissions and transmitting a first audio transmission using the first audio channel. A second audio transmission may then be received that contains an acknowledgment of the first audio channel. In certain instances, the second audio transmission may be received on a second audio channel. If no acknowledgment is received for the predetermined period of time, the first audio transmission may be selected using a second audio channel.

Abstract: Controlled access to a physical area or secured service is managed using sonic tones. A secret key is stored in a user device and in a security system, and then when access is desired, the secret key or a derivative thereof is encoded into a sonic tone which is transmitted. The sonic tone is received and decoded to obtain the encoded binary message, which is then compared to an expected binary message, and if there is a match, access is granted by the security system. In illustrated particular embodiments the secret key is used to generate a one-time password based upon the secret key and a randomizing factor, such as the current time.

Abstract: A disclosed device is configured to generate and transmit a sonic signal that encodes a symbol sequence, representing a data message, for delivery as audio content. The device includes an audio transmitter and a processor circuit. The processor circuit is configured to encode the data message as a sequence of symbols, with each symbol encoding a data value that is associated with respective phase characteristics of a transmitted audio carrier. The processor is further configured to generate audio samples of a digitized version of the sequence of symbols using the phase characteristics of the audio carrier associated with the symbols, and to control the audio transmitter to generate and transmit the sonic signal, based on the audio samples. A further disclosed device is configured to receive the sonic signal and to decode a symbol sequence by identifying symbols corresponding to determined phases of the sonic signal.

Abstract: A content management method uses a portable multifunction device 202 to detect human-inaudible acoustic signals 210, when that signal is heard from the surrounding environment by a device microphone 113 or is output by the device's audio circuitry 100. The device 202 extracts a code from the inaudible signal and supplies the code via wired or wireless communication 232, along with additional optional data regarding the device and/or its user, to a content management system 200. Upon receipt of the code, indicating the received inaudible signal 210 from the portable multifunction device 202, the content management system 200 may provide particular content or a pointer to that content to the portable multifunction device 202, the content being selected based on the particular inaudible signal received. Additional threshold triggers 502 may be delivered to require additional actions to unlock the content.