I seem to recall that the old Bell System spec for tone duration was
> 20ms, or 1/5th of a second. Some switches allowed you to go as fast as
> 10ms, which put the speed in speedial. :)
> Don't know how P8 generates tones, but is it possible they are right
> at the lower spec limit and your system isn't capable of decoding at > that rate?
I had a T-Berd on the line, and it didn't recognize any DTMF either. But after another couple of tests, I think I can definitely state that there is no difference in tone between keypresses ... for some reason his device or Packet8 is translating those keypresses to a monotone "blip" on inbound calls.