DTR Hangup on DZ lines?

[utzoo!decvax!ittvax!swatt]

As part of installing our Ungermann-Bass NET/ONE, I have  noticed
that  the  VAX  usually doesn't drop DTR on logout.  Since we use
the DTR signal to the NET/ONE to enable and disable  connections,
this  is  inconvenient.   In  looking  at  the sources for the DZ
driver, I noticed a line in dzopen that  set  was  commented  out
which  set  the  hangup-  on-last-close bit in the tty structure.
Also looking at the source for getty.c, I noticed  that  the  old
HUP  bit has gone away, so you can't set up alternate entries for
/etc/ttys that will do the trick.  

I can either change the DZ driver by un-commenting that line,  or
add  a  line  to  getty.c to set the hangup bit.  I would like to
have this work for  all  lines;  not  just  those  available  for
logons.  

Question: Does anyone have a reason why this mode should  not  be
          the default?  Can anyone comment on the 4.2bsd handling
	  of modem control in general?

		- Alan S. Watt
		(decvax!ittvax!swatt)		(UUCP)
		(decvax!ittvax!swatt at berkeley)	(ARPA, if it's working)

You can also reach me through duke if that's more convenient.