I asked whether it was possible to wire a serial cable for a console terminal
in such a way that power cycling on the terminal would not drop the Sun into
the PROM monitor. This generated a lot of interest (so I'm not naming names
except for some specifics) and is also a FAQ and is in the archives. In
fairness, and I try to be always fair (at least to myself), I did look in the
archive but I didn't find the answer because I failed to ask the right question.
The problem arise because power cycling a terminal produces noise which a Sun ZS
(serial port) driver interprets as a BREAK signal, so it does what it's meant to
do, and drops into the PROM monitor. Kevin Sheehan suggested hacking the ZS
driver so that a BREAK doesn't call the PROM and Hal Stern mentioned a Sun product
called CONSULT-ZSBREAK, which disables the halt-on-break behavior (for more info
call +1 415 336 2400). However neither of these would work for me as I need to be
able to drop into the monitor with a deliberate BREAK on occasions. The suggestion
which I intend to try is connecting pin 3 to pin 25 at the Sun end with a 4K7
resistor. This supposedly helps suppress the noise induced breaks while allowing
deliberate BREAKs to still be produced. There was also mention of a circuit
involving a diode . . .
Kindest regards,
Niall O Broin
UNIX Network Administrator, Stations and Communications Engineering Department
European Space Operations Centre nobroin@esoc.esa.de
Darmstadt, Germany Ph./Fax +49 6151 90 3619/2179
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:10:55 CDT