From: utzoo!decvax!cca!perry.gatech@Udel-Relay@sri-unix
Newsgroups: net.unix-wizards
Title: Re:  getty.c
Article-I.D.: sri-unix.3274
Posted: Tue Sep 14 17:47:51 1982
Received: Thu Sep 16 01:12:48 1982

From:     Perry Flinn 
Date:     10 Sep 82 17:13:19-EDT (Fri)
Regarding Andy Tannenbaum's message of 27 Aug 82:

In order to get a dialup line to hangup on logging out someone
has to issue the TICOHPCL ioctl code for the line.  This can be
done by getty or by login (the latter might be preferable since
there is already special-case code there for dialup lines).  It
is my impression, though I haven't taken the time to verify it,
that once this has been done for a particular line, it remains
in effect for that line forever; there is no corresponding ioctl
command to disable the feature.  This may account for the
inconsistent behavior mentioned.

An alternate solution is to modify the device driver to enable
the HUPCLS feature by default.  In fact, the dz driver in 4.1bsd
contains a line in the dzopen() function to do just that, though
the line is commented out. (Another curiosity!)

Of course, it is presumed that the cable running from the
distribution panel to the modem actually carries the modem control
signals (DTR in particular) and that they are not simply jumpered
in the connectors.