Where do I put a system in so it can call me?  Assume I have a system
named ucbvax that wishes to call my system.

Currently, when it connects, it gets told "you are unknown to me".
I get the impression that passwd is what I need to do, but I can't
figure out how, and I couldn't find a man page on it.  The uucico man
page isn't helping me much.

-s