Yes, you should de-emph the audio going to a DTMF deocder and autopatch, and pre-emph the audio coming from the autopatch is using a flat audio response system.
Joe M. david vanhorn wrote: > > > Then there's DTMF.. > > DTMF decoders HATE the high tone being louder than the low tone. > With pre-emphasized audio and a "flat" receiver, that's what you'll > get. > In the telco world, this is called "reverse twist". > Typical DTMF chips work over a 30dB range in amplitude. > > If your DTMF decode shows any sensitivity to the level adjustment, you > have "reverse twist". > > To fix that, de-emphasize before feeding the audio to the DTMF chip. > >
