Endpoint proximity pairing using acoustic spread spectrum token exchange and ranging information

A first endpoint generates an acoustic spread spectrum signal including a pilot sequence and a data sequence representing a token synchronized to the pilot sequence, transmits the acoustic spread spectrum signal, and records a transmit time at which the acoustic spread spectrum signal is transmitted. A receive time at which a second endpoint received the acoustic spread spectrum signal transmitted by the first endpoint is received from the second endpoint along with an indication of a second token as recovered from the received acoustic spread spectrum signal by the second endpoint. A separation distance between the first endpoint and the second endpoint is computed based on a time difference between the transmit time and the receive time. The first endpoint is paired with the second endpoint when the token matches the second token and the computed distance is less than a threshold distance.