Apparatus and method for determining co-location of services using a device that generates an audio signal

Methods and apparatus are provided for generating an audio signature. An audio signal generator generates an audio signal. A speaker responsive to the audio signal generator outputs the generated audio signal. A probe including a microphone samples the generated audio signal detected by the microphone. An audio signature generator is connected to the probe and generates an audio signature from the sampled audio signal detected by the microphone. The audio signature generator generates the audio signature without requiring detection of any additional audio signal. A transmitter connected to the audio signature generator transmits the audio signature to a communications channel.