This conversion would make sense for an attempt to convert audio saved from dictation app or software (.dct) as common MP3 music playable on everything. This is usually done with export function found in dictation programs, for example Express Dictate.
Convert NCH Software dictation codec file to Compressed audio and music file, mp3 songs or ringtones.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert dct to mp3 on Windows
A voice recording program that works like a dictaphone
Convert from dct file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.