Configuring Systems for Terminals, Printers, and Other Serial Devices (32022-90051)

Chapter 9 179
Describing Asynchronous Devices
How Operation Modes Set Functionality
The first serial port provides a connection to the local console. The port
is always fixed as LDEV 20. For backwards compatibility with the CIO
console, speed and parity on the console cannot be changed. The speed
is set at 9600 baud and the parity is set at none.
The second serial port is capable of connecting to the console port path
and connecting directly to the system. Although the second port can
connect directly to the system and be used as a user port, it should be
reserved for remote support access. It is configured as LDEV 21 by
default. Baud line rate is set at 9600 and parity is set at none.
NOTE The second serial port can be set as a remote console or a session port
but never both. When the user port is configured as a modem port for
remote support, the session is aborted after a powerfail, since modem
connections do not recover after a powerfail.
The third port, on HP 3000 Series 9X8 systems only, can support an
HP PowerTrust UPS connection. Refer to Chapter 5, “Configuring
Serial Devices (for Host-Based Management),” and Chapter 6,
“Configuring Serial Devices (for PC-Based Management),” for details on
how to configure this connection for host-based and PC-based
management environments, respectively. These devices are able to
provide status information about the condition of the UPS to the system
through this port. The system will respond and provide console
messages to the operator regarding the status of the UPS. This port
cannot be used for session access because the port is not configured as
session-accepting. This port is configured in SYSGEN as ldev 22 by
default; the baud rate is set at 1200 and the parity is set at none. For
more information on the UPS, refer to Performing System Manager
Tasks.
Session-Accepting Devices
Session-accepting devices are opened with the HELLO command, and
then a session is initiated. The session remains active until the user
logs off by typing the BYE command, or initiates a different session by
typing the HELLO command.
Session-accepting devices are terminals or PCs running in terminal
emulation mode. During a session, the terminal is used for interactive
(conversational) communication with the computer.
The terminal user can do any of the following:
• Enter MPE/iX commands.
• Run programs.
• Enter data.
• Receive output from the computer.