Silent channel - the audio signal energy level at the receiver output is below the energy threshold - normally encountered in speech pauses and on unoccupied frequency channels while in AM, USB, LSB and CW modes.

 Noise - the transmission is very noisy or the receiver is tuned to an unoccupied channel in an FM mode. The decision is made using the ratio between the signal energy and the maximum correlation level.

 Single tone - the demodulated signal is a single, continuous tone, with an energy level above the tone threshold - can be reported also on very slow CW transmissions.

 Two-tone AFSK - the signal appears to be a data transmission that uses two-tone AFSK modulation; the difference between the energy levels of the two tones must be below the AFSK threshold and both of them must be above the tone threshold.

 Data transmission - this type of signal has fast transitions around a DC offset, with periods between them corresponding to an integer number of bit periods.

 Voice or other - this is the default signal type, which the Classifier falls back to, for all unclassified signals.

While running, the Classifier turns on the indicator that corresponds to the currently detected audio signal type. Only one indicator is active at a time. If the receiver is in the scanning mode and the currently detected audio type matches one the of selected types, a scanning resume command is sent to the receiver program. This ensures that the scanning will not be interrupted by a transmission of no interest. The various threshold settings can be used to finely tune the classification process. The Restore defaults button can be used to revert to factory preset settings.