Category : Communication (modem) tools and utilities
Archive   : ODY150SH.ZIP
Filename : VT320.DOC

Odyssey VT320 Emulation
=======================

VT320 emulation was added to Odyssey as of version 1.41g.



General Notes.
--------------

This emulation does not support down-line loading of soft fonts, since the
VT200/VT320 font size is not usable on an IBM type display - we *may* add
this in future for users who want to download soft fonts to Odyssey with a
VGA cell size - however, this would make the host application Odyssey
specific, so it probably isn't a good idea. Another problem with this
emulation are multinational character sets which include the Danish 0 (an O
with a slash through it). The VGA character set unfortunately does not
include this character. If we do add VGA soft fonts in the future then
that will deal with this problem. The problem with soft fonts however is
that it will tend to mess up TSR pop-up programs etc which will certainly
assume the standard IBM character set in use in the PC, so if we add this
feature we will certainly make it optional.

A VT320 terminal has the option of running in either "7 bit" or "8 bit"
mode. When this emulation runs in "7 bit" mode it reports the terminal
type on the Odyssey status line as "VT320-7b", and in "8 bit" mode it
reports "VT320-8b". Odyssey will run this emulation in eight bit mode only
if parity is set to "none" and "Strip Parity Bit" (in setup/general) is
set to "off", at the time that the terminal emulation is loaded.


Keyboard
--------

The notes in the Odyssey manual regarding keys in the VT100 emulation also
apply to the VT320 emulation. However, VT320 has a number of extra keys,
in particular it provides up to 20 programmable function keys. For this
reason we recommend that you use an enhanced keyboard (102 key) with the
VT320 emulation, a keyboard which is as close as PC keyboards get to the
DEC equivalent.

For convenience, applicable sections of the notes from the VT100 emulation
are repeated here:-

The numeric keypad on an IBM PC does double duty as a cursor pad. When
NumLock is set the VT100 emulation will generate numbers from keypad keys
if the keypad is in numeric mode, or application sequences in alternate
mode. The '+' key on the keypad generates the same sequence in alternate
mode as the ',' which occupies this position on the VT100 pad.

If NumLock is not set then the keypad generates cursor sequences, either
ANSI or application depending on the cursor key mode.

Since the standard PC keypad does not have PF1-PF4 or Enter, these keys are
generated using CTRL-F1 to CTRL-F4, and CTRL-F5 for Enter.

On the main keyboard, the backspace key on the PC generates BS (ASCII
8) and not DEL (ASCII 127) which a VT100 user may expect. You can reverse
this using the "BS key generates..." option in Setup/General.

Note: A standard VT100 terminal has 24 lines. If you leave the
Odyssey main menu line enabled then the Odyssey display area will only be
23 lines. For complete compatibility with mainframe applications you
should disable the menu line when VT100 is used.

VT100 emulation will not work in 43/50 line modes on the EGA/VGA.

The Odyssey VT100 emulation does support 132 column mode, but the PC hardware
is not capable of displaying this on one screen. Odyssey therefore implements
"panning" which treats the physical display as a "window" on which you can
view a selected portion of the 132 column display. The following keys control
the portion of the 132 column region shown:-

Ctrl-Home ...... Show left side
Ctrl-End ...... Show right side
Ctrl-Left Arrow ...... Pan 10 columns to the left
Ctrl-Right Arrow ...... Pan 10 columns to the right.


Added VT320 specific information:-

A VT200/VT320 keyboard adds a separate arrow key cluster, a cluster of
editing keys (Find/Insert etc), and 20 function keys, the first five of
which generate no keystrokes, but serve local terminal functions.

Arrow key cluster:
If you have the old PC keyboard then you must use the numeric keypad
keys, as described in the VT100 notes. On an enhanced keyboard you may
use the separate arrow key cluster, which is identical to the VT320
equivalent.

Editing keys:
An enhanced keyboard is far more convenient for this than the old PC
keyboard. This is the mapping of PC key to VT320 equivalent:-

PC key VT320 equiv.

Insert Insert
Delete Remove
Home Find
End Select
Page Up Prev Screen
Page Down Next Screen

Note that although the appearance of the PC cluster is similar to the
DEC equivalent, the keytops are different. The emulation follows the
PC keytops (where possible), rather than the VT320 keytops, otherwise
things could get rather confusing, however you should beware of help
messages from the host system (such as in VMS EDT), which indicate the
correct keys graphically. If you have the old PC keyboard then you
must use the numeric keypad (remembering to toggle NUMLOCK off), but
the same key mapping applies.


Function keys.
As noted above, the first five function keys serve local terminal
functions both in Odyssey and on a real VT320. This is convenient,
since it means that Odyssey F1 (help) can still work. Other keys:-

PC key VT320 equiv.

F6 to F10 F6 to F10
ShiftF1 to ShiftF10 F11 to F20

For convenience, for those users with enhanced keyboards, VT320 key
F15 (Help) is duplicated on PC key F11, and F16 (Do) is duplicated on
PC key F12.