In one embodiment, a method includes receiving ultrasound frequency sweeps in a sound receiving device. Each of the plurality of ultrasound frequency sweeps is centered on one of at least two predetermined frequencies. The method also includes converting the ultrasound frequency sweeps into an ultrasound message based on a central frequency of each of the ultrasound frequency sweeps received, and placing the ultrasound message into a receive buffer. Then at least a network address is extracted from the ultrasound message, and the network address is used to establish a communication session over a data network with a telecommunications device.