ttyS0 vs cua0

[Peter S Galbraith <GalbraithP@dfo-mpo.gc.ca>]

How universal is the use of ttyS0 instead of cua0 in other
distribution (e.g. Red Hat)?  I told the upstream maintainer 
of powstatd (a UPS monitor) that I has changing cua0 to ttyS0 in
the docs and config file for Debian, and he said he'd changed it
upstream too if that's what everybody uses.

Docs such as the UPS-HOWTO use either at various places.
The Serial-Programming-HOWTO uses only ttyS0 style.

Thanks,
Peter