Installation guide

should use the ECU to complete any environment configuration before
setting up and using a modem as a console device.
2.2.1 Setting Up a Console Port
The following sections provide an overview of the steps required to set up a
serial line console port and set up the remote modem for dial-in. It is
assumed that your local (dial-out) modem is already installed and
configured for use.
2.2.1.1 Connecting the Modem to COMM1
The CONSOLE environment variable on the remote system should be set to
serial.
Refer the hardware documents supplied with your modem for connecting
the modem to your system. Consult the modem
(7) reference page to obtain
the correct modem settings and for instructions on how to create the
appropriate system file entries. In particular, the cons entry in
/etc/inittab file should be modified so that the getty or uugetty
process sets up the COMM port correctly. This line is similar to the
following example:
cons:1234:respawn:/usr/sbin/getty console console vt100
This line should be changes as follows if you are using a modem set to run
at a baud rate of 38,400 as a console device:
cons:1234:respawn:/usr/sbin/getty console M38400 vt100
2.2.1.2 Setting the Configurable DCD Timer Value
The Tru64 UNIX serial driver has been modified to allow the Carrier
Detect (DCD) timeout value to be configurable. The default value for this
timer is 2 seconds, which is in accordance with the DEC STD-052 standard
and is acceptable for most modems. This timer is used to determine how
long the driver must wait when the DCD signal drops, before declaring the
line disconnected and dropping the DTR and RTS signals. Some modems
expect DTR to drop in a shorter time interval, so refer to your modem
documentation to verify the interval.
The timer can be modified via the /etc/sysconfigtab file or the
sysconfig command to set the timer to 0 (no timeout period), 1, or 2
seconds. To set the timer via /etc/sysconfigtab, edit the file and
include the following:
ace:
dcd_timer=n
System Administration Tools and Methods 2–5