Hi I am looking for something that can do DTMF Detection in realtime
for linux software over the sound card using alsa or oss.

I think if you program receive the data which includes DTMF tone from
network layer, the reasonable place to judge DTMF is not sound card
but network layer.
You can fetch the data packet and analyse it, if the packet's loading
is DTMF, there are many flags to indicate it. Need to know more?
please reply it. Good luck.

Umm it is from Skype that needs to convert so my software will be able
to work with the user that is calling from a land line. If you have a
way to read the DTMF tones from skype that would be awesome.
Otherwise, I know where I can find the forumlas I need something that
can do it for me.