Install soundmodem by entering the following commands in the terminal:
sudo apt update sudo apt install soundmodem
Description:
Sound Card Amateur Packet Radio Modems
This package contains the driver and diagnostic utility for the userspace SoundModem suite by Thomas Sailer. . This package allows you to use any soundcard supported by the kernel as an Amateur Packet Radio modem.
Homepage: http://gna.org/projects/soundmodem
Version: 0.20-5
Section: universe/hamradio