I've installed minimodem on a server running Ubuntu. I've read through the documentation but still having trouble. I want to input a text file and use frequency shift keying to output an audio file. 
SFK to convert text to sound with minimodem?
audio;conversion;modem;telephony
A naive answer to this question is:cat example.txt | minimodem --write 1200 -f converted-example.wavAfter the generation, you may check with this commandminimodem --read 1200 -f converted-example.wav > regenerated.txt && diff example.txt regenerated.txtFor further usage, check the man page again.