Just to provide more detail, hylafax talks to iaxmodem over a pty, just
as hyla would talk to a hardware modem over a tty (serial or usb link).
If you don't have asterisk ported to aix, you can leave it on a linux
box. It will help if the two boxen have a private point-to-point
ethernet link, but things will still work through a decent switch.
James Cloos <firstname.lastname@example.org> OpenPGP: 1024D/ED7DAEA6