I did some more research and think i can answer my own question, I found this reference describing a linksys tone.
For example, the default dial tone (USA) looks like:
350@-19,440@-19;10(*/0/1+2)
This means:
Frequency 1 is 350 Hz @ -19 dBm
Frequency 2 is 440 Hz @ -19 dBm
There is one Cadence section.
It is 10 seconds long.
It is on "forever" (that's what the star is), it is never off (that's what zero means here), and it plays both tones 1 and 2.
I think this would be the translation of my question in the originating post?
425-16,425-16,450-16;10
dial tone generated from three frequencies
425hz at -16db
425hz at -16db
450hz at -16db
The expiration time is 10 seconds
it has only one cadence segment, which has infinite tone active time.