soundmodem(8) on Linux
The text b652b6259625, as Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
Soundcard modem driver
Flags it lists
-
-M -
-R -
-S -
-c -
-h -
-s -
-v