A rudimentary example of DTMF encoding/decoding in MATLAB
https://www.mathworks.com/matlabcentral/fileexchange/91500-simple-dtmf-encoder-decoder
While this is the current location of these files, I have absolutely no interest in interacting via GitHub or using any of its features. GitHub is just the only means of hosting that's compatible with the lopsided migration options available via the Mathworks File Exchange.
To install, just look at the Releases section on the right, download the zip file, unpack it somewhere appropriate, and then add the resulting directory (and its subdirectories) to the MATLAB path.