Tone detection includes receiving a series of frames having a signal containing a tone and locating a first frame in the series of frames in which there is at least a partial, tone. The signal energy of the first frame may then be compared to the signal energy of a full tone frame or compared to the signal energy of a frame. A start time of the tone in the signal may then be determined. An end time of the tone in the signal may be determined by locating a last frame in the series of frames. The duration of the tone signal may be determined based on the determined start time and end time of the tone in the signal.