A remote ring monitor for a mobile communications device comprises an audio sensor to detect a sound signal emitted by the monitored device and one or more indicators which may provide visual, auditory or tactile alert signals to the user. A plurality of indicators may be used to indicate various different audio signals received. The audio sensor may comprise a microphone, a codec and digital signal processor. In certain embodiments, an encoded ring tone is downloaded to a mobile communications device to be monitored so as to enhance the selectivity of the monitoring device. The audio sensor may be remote from the indicator and the two may be in communication via a radio-frequency link.