un-dedicating a line to a dialer

[Steve Burbeck]

We (and many others I would guess) have a similar problem.  We
solved it without kernel hacks.  The trick requires the ability to
detach the tty line and reattach it later, which some systems do
not support (ours is Perkin-Elmer V7 which has detach and attach
commands).  All you need to do is have two L.sys files: I call them
L.sys.Any and L.sys.Never.  During normal times when the tty is
attached and used for dial-in, L.sys is linked to L.sys.Never in
which all sites that require use of the tty for dial-out have
Never in the call-time field so mail for them is spooled, but
uucico will not attempt to dial out.  When dial out is desired
(e.g., by crontab every night or whenever the super-user desires)
a shell script  called uucp_out tests to be sure that the line is not
in use, and if not, detaches the tty line, relinks L.sys to L.sys.Any,
and starts uucico.  L.sys.Any has Any in the call-time field for those
sites that require dial-out.  When uucico is done, L.sys is relinked
to L.sys.Never and the tty line is attached.

This may seem like a kludge, but it is a lifesaver for those of us
that do not have access to kernel source.  The system has worked
smoothly for months now.