This is often a problem where a university has several modem lines and several thousand students trying to use them...
Make an entry for your university in /etc/remote
and use @ for the pn capability:
big-university:\
:pn=\@:tc=dialout
dialout:\
:dv=/dev/cuaa3:br#9600:at=courier:du:pa=none:
Then, list the phone numbers for the university in
/etc/phones:
big-university 5551111
big-university 5551112
big-university 5551113
big-university 5551114
tip will try each one in the listed order, then give up. If
you want to keep retrying, run tip in a while loop.