Product guide

116 Configuration Software and Utilities
117MAXDATA PLATINUM 90004R Server System
The Setup/EMP option for handshaking must be set to CTS/RTS + CD for optimum performance. The
CD refers to carrier detect. If EMP is sharing the COM port with serial redirection, the handshaking must
be set to CTS/RTS+ CD. In selecting this form of handshaking, the server is prevented from sending
video updates to a modem that is not connected to a remote modem. If this is not selected, video
update data being sent to the modem inhibits many modems from answering an incoming call. An
EMP option utilizing CD should not be used if a modem is not used and the CD is not connected.
Once console redirection is selected via Setup, redirection binary is loaded into memory and activated
during POST. While redirection cannot be “removed” without rebooting, it can be inhibited and
restarted. When inhibited, the serial port is released by redirection and might be used by another
application. Restarting reclaims the serial port and continues redirection. Inhibiting/restarting is
accomplished through the following INT 16h mechanism. The standard INT 16h (keyboard handler)
function ah=05h places a keystroke in the key buffer, just as if an actual key had been pressed.
Keystrokes so buffered are examined by redirection, and if a valid command string has been sent, it
is executed. The following commands are supported in this fashion:
• Esc-CDZ0 - Inhibit Console Redirection
• Esc-CDZ1 - Restart Console Redirection
In order to inhibit redirection, the software must call INT 16h, function ah=05h ve times to place the
ve keys in the key buffer. Keystrokes sent to the INT 16h buffers for purposes of invoking a command
are buffered, and should be removed via the normal INT 16h calls to prevent these keystrokes from
being passed on to another application.
Keystroke Mappings
During console redirection, the remote terminal (which may be a dumb terminal or a system with
a modem running a communication program) sends keystrokes to the local server. The local server
passes video back over this same link.
For keys that have an ASCII mapping, such as A and Ctrl-A, the remote simply sends the ASCII character.
For keys that do not have an ASCII mapping, such as F1 and Alt-A, the remote must send a string
of characters, as dened in the tables below. The strings are based on the ANSI terminal standard.
Since the ANSI terminal standard does not dene all the keys on the standard 101 key U.S. keyboard,
mappings for these keys were created, such as F5 - F12, Page Up, and Page Down.
Alt key combinations are created by sending the combination ^[} followed by the character to be Alt
modied. Once this Alt key combination is sent (^[}), the next keystroke sent is translated into its
Alt-key mapping (that is, if ^[} is mapped to Shift-F1, then pressing Shift-F1 followed by ‘a’ would
send an Alt-a to the server).
The remote terminal can force a refresh of its video by sending ^[{.
Presently, unusual combinations outside of the ANSI mapping and not in the table below, are not
supported (for example: Ctrl-F1).