There seem to be a few requests a month regarding DTMF. I have never had an application requiring knowledge of DTMF so therefore I have never used any of those devices. While searching for info for another thread here I ran across the Holtek HT9200 and HT9170 devices ( http://www.holtek.com/english/pr... ). I did a search here and found only one reference to the HT9170 (no references to the HT9200).
Since I never see anyone recommend these devices I was wondering if that means these devices are outdated, hard to get, hard to work with, etc.?
There is no way I am the first person to come across these devices so I am asking this before I file this info away for use later when someone asks about DTMF again :-) . Maybe this just needs to go in the trash ??
Dave VanHorn apparently has used the HT9200...that is how I initially found this info.