Automatic provisioning of distinct ring-tones for co-located telephones

A controller ensures that ring-tones of a relatively-small pool of distinct ring-tones are individually assigned to telephones of a group of telephones in such a way as to maximize the physical separation of telephones with the same or similar ring-tones. One telephone after another generates an audio signal, such as a chirp or a ring-tone, while the other telephones listen for the audio signal and report results of their listening to the controller. The controller uses the results to assign ring-tones to the telephones. A graph-coloring algorithm may be used to make the assignments.