at http://wiki.openpbx.org/tiki-index.php?page=Easy+route+to+building+OpenPBX.o...
there is the following adduser command:
adduser --no-create-home --ingroup openpbx --disabled-password --disabled-login openpbx
This does NOT seem to be the right format for Centos. So far, using man, I have come up with;
adduser -M -g openpbx
What else do I need?