Log Message:
Initial import of ptyusart-0.3.1:
This is a serial module for gpsim, connecting the virtual Rx/Tx lines
to a pseudo-tty (pty). You can then use your usual serial tools (cu, tip,
minicom, etc ...) on this pty as you would do on a real serial port on
your Unix workstation.

Only for NetBSD for now. It should be easy to get it working on others BSD
systems. More work is needed for others Unix and Unix-like systems.