Transfer Of A Modem Session - IBM pSeries 630 6C4 Service Manual

Terminal Emulators
The service processor is compatible with simple ASCII terminals, and therefore compatible with most
emulators. When a remote session is handed off from the service processor to the operating system,
agreement between terminal emulators becomes important.
The server's operating system will have some built-in terminal emulators. You may also have a
commercially available terminal emulation. It is important that the local and host computers select the
same or compatible terminal emulators so that the key assignments and responses match, ensuring
successful communications and control.
For best formatting, choose line wrap in your terminal emulator setup.
Recovery Procedures
Situations such as line noises and power surges can sometimes cause your modem to enter an undefined
state. When it is being used for dial-in, dial-out or ring indicate power-on, your modem is initialized each
time one of these actions is expected. If one of these environmental conditions occur after your modem
has been initialized, it might be necessary to recover your modem to a known state.
If your modem communicates correctly with remote users, it is probably in control. It may be wise to
occasionally change some of the functional settings and then change them back, just for the sense of
security that the modem is communicating, and to ensure it has been initialized recently.
If your system is particularly difficult to access physically, another strategy is to protect it with an
Uninterruptible Power Source (UPS) and a phone-line surge protector.
In case recovery becomes necessary, shut down your system using established procedures. Disconnect
the power cable and press the power button to drain capacitance while power is disconnected. Disconnect
and reconnect modem power, and then reconnect system power to completely reinitialize your system.

Transfer of a Modem Session

Because many modem command variations exist, the sample modem configuration files located at the end
of this appendix have been written to capture the largest number of workable modem settings.
The modem command &Dn (where n is a number) generally sets the modem response to the Data
Terminal Ready (DTR) signal from the server's serial port. The desired response is that the modem will
hold a connection while DTR is enabled, and drop the connection when DTR is released. Using this
mechanism, the server hangs up on a connection under normal conditions.
Consult your modem manual for its specific response scheme for the &Dn command.
Two strategies are available for dealing with the modem's response to DTR:
v Recovery
v Prevention
Before you use one of these strategies, determine if your server's modem is set up correctly to respond to
DTR.
With the remote terminal connected to serial port 1 and defined as the Primary Console Device, there are
two tests you can perform:
1. Will the modem drop the connection after the System initialization complete message displays at
the remote terminal?
If Yes, the modem is set up correctly.
Appendix F. Modem Configurations
601