DTMF tones consist of a mixture of tones from two frequency groups. For DTMF generation these settings define the relative amplitude of both frequency groups. The amplitudes can be set to be equal for both groups, to be twisted by 2dB (the high frequencies are more attenuated on some phone lines, so they are sometimes set 2dB higher than the low frequency group), or to be set independently for both frequency groups.
The duration and separation of tone bursts can be set, as well as the duration of pauses (silences), and of file leading and trailing silences (silent padding before and after the tone sequence).
For DTMF detection, the minimum tone amplitude setting defines the threshold level above which DTMF tone pairs are considered to be valid DTMF digits. You can also set the maximum difference in amplitude (twist level) between the high frequency tone and the low frequency tone for DTMF signals to be considered as valid. Finally, you can set the minimum duration for a DTMF signal to be detected as valid and the maximum allowable gap (loss of signal) in such a DTMF signal. If there is a gap in the tone below this value then only one tone is seen. If the gap is above this value, then two DTMF tones are seen. It is important to set all these values at realistic levels or DTMF detection will be totally meaningless.