4/400 + ALM-1: will it work?

[Ed Arnold]

In sun-spots v10n7, I wrote with regard to usage of an ALM-1 on a 4/490
running 4.1:

|If you do decide to run it on your 4/400, keep in mind that the login
|shells on ALM-1 ports will become a security hole, cuz they'll never
|receive hangup signals.

I subsequently received the following reply from a member of the Sun
technical staff:

|This is not true.  See mti(4S) for how to wire your ALM-1 lines to
|handle carrier properly.  See ttysoftcar(8) for how to set up the
|system to pay attention to carrier.

On a 4/490 running 4.1, which has a single ALM-1, we have done the
following:

1) We have set the "carrier detection mode" flag of all ALM-1 ttys to
   something other than "local".  (It has been set to "foobar", which seems
   eminently appropriate in this case.  :-)) "ttysoftcar" is executed from
   our rc script.

2) The ALM-1 is fed by a Gandalf PACX serial port switcher.  We have
   OR-wired its DCD line to the ALM-1's CTS, DSR, and DCD pins, presumably
   satisfying this paragraph from the WIRING section of the 4.1 MTI(4S) man
   page:

   |The  Systech  requires  the  CTS  modem  control  signal  to
   |operate.   If the device does not supply CTS then RTS should
   |be jumpered to CTS at the distribution panel (short  pins  4
   |to  5).   Also,  the  CD (carrier detect) line does not work
   |properly.  When connecting a  modem,  the  modem's  CD  line
   |should  be  wired  to  DSR, which the software will treat as
   |carrier detect.

   (It is interesting to note that the same wired-OR arrangment is
   used on Sun 3/280s and 4/280s with ALM-1s here, running 4.0.3,
   on which it works perfectly.)

I am interested in receiving e-mail from three classes of people (will
summarize of course):

1) Users who have been able to make the ALM-1 work on any 4/400, i.e. it
   will generate a SIGHUP to a login shell when CTS, DSR, and DCD go away.
2) Users who have tried every combination under the Sun, proving to
   themselves that it can't be made to work.

Thanks in advance,
era at ncar.ucar.edu