DTMF tone generation
I work in telephony. Not only that, I live in a location with crap mobile signal. I also work in shielded server and comms rooms.
What I found myself doing on Android, was purchasing a separate DTMF generator which would "speak" the DTMF tones out of the loudspeaker. Useful at home because I could "speak" the tones in to the domestic phone without having to keep a separate phone book.
My suggestion is thus ...
Settings -> App -> People ... have an option for "Enable DTMF button"
Which would take the "Call - SEND SMS" to become "Call - Send SMS - Speak DTMF" for each contact.