The mgetty-voice package contains the vgetty system, which enables
mgetty and your modem to support voice capabilities. In simple terms,
vgetty lets your modem act as an answering machine. How well the
system will work depends upon your modem, which may or may not be able
to handle this kind of implementation.
Install mgetty-voice along with mgetty if you'd like to try having
your modem act as an answering machine.