On the right columne of the DTMF signalling window:
- First digit delay is the pretime
- The next two options (separate length of the first digit, * and #) we don't use yet (if you want, I can patch it to the code as well)
- The last one (DTMF Rate) should be converted to our digit/pause duration. There are only 3 values, 5, 6 and 10. For 10, it's 50ms tone /50ms pause, for 5 I think the best will be 150ms tone and 50 ms pause and for 6 the exact value is 117 ms of tone but I think we can round it down to 100 ms tone / 50 ms pause. So the conversion will just switch between 50, 100 and 150 ms of tones and the pause will be fixed to 50.
However, I don't like this option, much better would be to set individually the length of tones and pauses. But our Chinese programmers decided to go this way, so let's follow it..