Minimodem is a command-line program which decodes (or generates) audio modem tones at any specified baud rate, using various framing protocols. It acts a general-purpose software FSK modem, and includes support for various standard FSK protocols such as Bell103, Bell202, RTTY, TTY/TDD NOAA SAME, and Caller-ID. Minimodem can play and capture audio modem tones in real-time via the system audio device, or in batched mode via audio files.

source: L