Abstract: Methods and systems for estimating Supervisory Audio Tone (SAT) strength during data transfer and for a short time period thereafter. The SAT during this period is regarded as being identical to the strength measured just before the data transfer was started. In an alternative embodiment, a probabilistic algorithm can be used wherein previous measurements are used to predict the SAT strength during and for a period after data transfer. Where the present invention is used in a mobile radio telecommunications system of the type in which analog information is transmitted between at least one base station and a number of mobile stations, a method for supervising the quality of a connection between the base station and a mobile station includes transmitting data between the base station and the mobile station during which a SAT is not transmitted and using pre-data transfer SAT measurement for radio transmission quality supervision during at least a time period of said data transmitting step.