uucico hangs on SCO Unix 3.2.2

[Ralf U. Holighaus]

We have our communication server running with SCO Unix 3.2V2.0. It runs
fine, does all our mail & news.

As we have one important XENIX machine with many users and no SCO sendmail
or MMDF on it, we connected it with a serial cable and made it poll every
five or ten minutes for new mail on the UNIX system.

Sometimes it happens, that the uucico process on the UNIX system keeps 
hanging althoug there is no connection any more from the XENIX system.
Even a kill -9 will not be able to kill it and therefore, the line is not
useable any more. What we do is reboot the UNIX system, but thats no work-
around...

Any ideas what might cause the problem?

Regards

Ralf.