Configuring Systems for Terminals, Printers, and Other Serial Devices (32022-90057)

Describing Asynchronous Devices
How Operation Modes Set Functionality
Chapter 9
163
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.
• Place the terminal under partial control of a program running on the computer.
• Communicate with other terminal users and with the system operator.
• Transfer data and control information between the computer and a slaved device
connected to the terminal.
• Change the line speed of the terminal.
• Terminate the session.
Also, session-accepting devices that are not connected through a PAD or Telnet/iX and
are not configured for switching can temporarily obtain partial system console
functionality by using the CONSOLE command. A terminal that is the logical console can
receive console messages, execute commands that do not require
[CTRL]-A
, and return
console control to the system console (through the CONSOLE command).
Programmatic Devices
Programmatic devices run under the control of a program on the computer. The program
accesses the device through the file system by treating the device as a file (device file).
The file system passes information from the controlling program to the software which
communicates directly with the device.
A programmatic device is captive of the program because access to the device is through
the program only. For instance, MPE/iX commands cannot be executed from a terminal
under the control of a program unless the controlling program initiates the command. A
programmatic device can be used for input, output, or both, depending on the device and
how the controlling program opened it.