There is *no* difference between the PortMaster and every Unix system
I've ever seen in this respect - they will both redo the
login: (or equivalent) prompt indefinitely if you just send CR or LF
characters.
If your portmaster switches over to the Password: prompt, it's because
it has received some other character(s) *before* the CR/LF, and
(rightfully) asumes they're a userid. Presumably these are coming from
your modem - make sure you have set "modem control on" on the PM; if
this doesn't help you may need to tweak your modem settings to get it to
shut up.
Btw, this mailing list is for issues with PortMasters and RADIUS.
Regards
--Per Hedeland
per@erix.ericsson.se