Understanding VT bidirectional language support (Arabic and Hebrew)

Editing functions

1. On the Edit menu, click Text Type, Text Orientation or Numeral Shape.
2. Select the appropriate values for bidirectional Cut/Copy & Paste:
• Text Type - Visual or Logical
• Text Orientation - Left to Right or Right to Left
• Numeral Shape - National, Nominal or Contextual

The Numeral Shape menu option is available for Arabic session only.

Setting display options

To set the bidirectional display options:

1. Right-click a configured session icon.
2. Click Properties.
3. Select a bidirectional Host Code Page.
4. Click Language.
5. Select the appropriate values for:
• BIDI Mode - On or Off
• Numeral Shape - National, Nominal or Contextual
• Cursor direction - Left to Right or Right to Left
6. Click OK.

To change these settings in an active Host On-Demand session:

1. On the View menu, click Bidi Mode or Numeral Shape.
2. Select the appropriate values:
• Numeral Shape - National, Nominal or Contextual
• BIDI Mode - On or Off

The Numeral Shape and BIDI Mode menu options are available for Arabic session only. The Cursor direction menu option is available for Hebrew session only in visual text mode.

Smart ordering on

A segment is a group of characters that have the same attributes. In this mode, text is ordered segment by segment. To enable this mode, select View > Bidi display options > Smart Ordering, and select On.

In this mode, you can indicate whether you want the underline attribute to be visible or invisible. Select View > Bidi display options > Show text attribute, and click on the On checkbox if you want the underlining to be visible.

Smart ordering off

In this mode, text is displayed with the default attributes. To enable this mode, select View > Bidi display options > Smart Ordering, and select Off.

Remapping bidirectional keys

1. Right-click a configured session icon.
2. Click Properties.
3. Select a bidirectional Host Code Page.
4. Click Keyboard Remap.
5. Press the key you want to remap.
6. Select the bidirectional function that you want to remap to that key.

• Screen reverse (for logical text type only )
• National keyboard layer
• Latin keyboard layer
• Set/reset right-to-left cursor direction (for Hebrew session and visual text type only)
• Toggle between 7-bit and 8-bit character set modes (for Hebrew session only)
• Adjust the column heading (for Arabic session only)

Bidirectional support for printing in a VT session

To properly print Arabic or Hebrew text, the following should be implemented:

• Before submitting a printer job, send a start Esq-sequence to the printer that makes the printer use a national character set and an appropriate font
• Convert any national character from host codepage to printer codepage
• After completing a printer job, send a finish Esq-sequence to the printer that reinstates the printer's default settings

The start and finish Esq-sequences are printer-dependent. Currently, VT printing does not use Printer Definition Files (PDFs). But the PDF file is used for Bidirectional sessions to define host-to-printer ASCII translation and control codes sent at the start and the end of each host print job. See Host Printing Reference for more information about creating and using of Printer Definition Tables (PDTs) and Printer Definition Files (PDFs).

Choosing a printer definition file (PDF)

For a VT bidirectional session, select a PDF from the Printer tab of the Session Properties dialog box. For a non-VT bidirectional session, the Printer tab of the Session Properties dialog box includes a list of PDFs relevant for a VT session.

Creating a printer definition table (PDT) for a VT bidirectional session

To be used for a VT session, the PDT should include the parameter VT_PRINT?=x, where x is a number that identifies a language. The following identifiers are currently supported:

• 0 - Ignore
• 1 - Arabic
• 2 - Hebrew

If the parameter does not exist or is set to 0, the PDT should not be used for VT printing and is not displayed in the list of PDFs. If the parameter is set to one of currently supported languages, the PDF is not displayed in the Session Properties dialog box for a 3270 printer session.

Following is an example of a segment of a PDF file with parameters that are important for VT bidirectional printing. This PDF is designed for Hebrew printing on HP LaserJet 4 printer.

...
/* user-defined macros */
BEGIN_MACROS
...
...
SUL    EQU 1B 26 64 33 44    /* Start Underline             */
CUL    EQU 1B 26 64 40       /* Cancel Underline            */
SBP    EQU 1B 28 73 31 42    /* Start Bold Printing         */
CBP    EQU 1B 28 73 30 42    /* Cancel Bold Printing        */
CS1    EQU 1B 28 38 55       /* Roman 8 char set 1          */
CS2    EQU 1B 29 38 55       /* Roman 8 char set 2          */
SFT    EQU 1B 28 31 35 51 1B 28 73 30 70 31 30 2E 32 36 68 31 32 2E 30 76 30 73 30 62 39 38 54 
ARA   EQU 1
                                  /* Hebrew char set */    
END_MACROS
/**********************************************************************/
/*                     Control Codes                                  */
/**********************************************************************/
 /* user defined sequences */
 ......
 START_JOB= CUL CBP SFT
 END_JOB= CUL CBP CS1  
 VT_PRINT?=ARA
 ......
 /**********************************************************************/
 /*                      Character Definitions                         */
 /**********************************************************************/
 /*example: convert ASCII from 1255 (Hebrew codepage on Windows 98) to 862 (Hebrew codepage used on printer)*/
 /* the table is in format source=destination */
 .....
 E0=80
 E1=81
 E2=82
 E3=83
 E4=84
...

Other PDT parameters need not be processed for base bidirectional support and will be ignored for a VT session.

PASSTHRU mode support

The VT terminal uses PASSTHRU mode to send data to a printer without displaying it on a screen. The data can be plain text or binary data, such as image or Postscript text. See your VT terminal documentation for more information about PASSTHRU mode.

Some host applications send text that is already converted to the printer codepage. In these cases, the emulator should not perform any conversion.

By default, ASCII conversion for PASSTHRU mode is disabled, because the VT emulator cannot determine whether conversion is needed. To enable conversion, select Edit > Convert to printer codepage. For VT print modes other than PASSTHRU, ASCII conversion is enabled by default.

Understanding bidirectional Hebrew support

The bidirectional Hebrew support in VT enables the program to emulate an English/Hebrew VT 220 display terminal. Special Language and bidirectional functions are added to the list of standard functions supported by the emulation program.

Configuring a workstation
Setting text types
Understanding Hebrew and bidirectional functions
Summarizing bidirectional key combinations for Hebrew
Understanding the Operator Information Area (OIA) in terminal emulation mode

Configuring a workstation

1. Right-click a VT configured session icon.
2. Click Properties.
3. Select ISO Hebrew Supplemental (code page 916, 8-bit), or DEC Hebrew (code page 1349, 8-bit), or Hebrew NRCS (code page 1134, 7-bit) for the Host Code Page.
4. Click the Screen tab and either leave the default bitmap font HEB3270 to be the active font for display or select the system font, Courier.

Setting text types

The bidirectional session supports two text modes and their corresponding manipulation: Implicit (Logical) and Visual. In the Implicit text mode, characters are stored in same order that they are entered. The text is transformed into its visual form only when it is displayed. In the Visual text mode, characters are stored in the same way that they are displayed on the window. To switch between Visual and Logical text modes:

1. Right-click a configured session icon.
2. Click Properties.
3. Select a bidirectional Host Code Page.
4. Click Language.
5. Select the appropriate values for Text Type.
6. Click OK.

The visual text mode is available for Hebrew session only.

Understanding Hebrew and bidirectional functions

Language selection

The key combination Ctrl+N or Ctrl+L allows you to change the language layer. If the language layer is Latin, pressing Ctrl+N changes the language layer to Hebrew. If the language layer is Hebrew, pressing Ctrl+L changes the language layer to Latin.

 

Cursor direction

The key combination Ctrl+D allows you to change cursor direction. If current cursor direction is left-to-right, pressing Ctrl+D changes it to right-to-left, and back again. This function is allowed for visual text type only.

When cursor direction is set to right-to-left, this does not affect cursor addressing and moving, insert and delete characters, erase in line or erase in display. The following functions are affected by right-to-left cursor direction setting:

• Backspace (the cursor moves one position to the right)
• Carriage return (the cursor moves to the rightmost position on the current line)
• Line feed (the cursor moves to the rightmost position of the next line)
• Typing in the auto wrap mode (current line is continued from rightmost position of the next line).

Character set modes

This function is activated by the Ctrl+B key sequence and switches between 7-bit and 8-bit character sets. If the current character set is DEC Hebrew (8-bit) or ISO Hebrew Supplemental (8-bit), pressing Ctrl+B changes the current character set to Hebrew NRCS (7-bit). If the current character set is Hebrew NRCS (7-bit), pressing Ctrl+B loads one of two 8-bit character sets based on the following rule:

• If the session is configured with one of the 8-bit character sets, that session's 8-bit character set will be loaded.
• If the session is configured with 7-bit character set, ISO Hebrew Supplemental will be loaded.

The current language layer and cursor direction are not changed.

 

Screen reverse

This function is available for Logical text mode only. The key combination Ctrl+S reverses the screen image. If the screen orientation is left-to-right, press Ctrl+S to reverse the screen image to right-to-left. If the screen orientation is right-to-left, press Ctrl+S to reverse the screen image to left-to-right.

Summarizing bidirectional key combinations for Hebrew

Understanding the Operator Information Area (OIA) in terminal emulation mode

In the host session, the bottom line of the screen is called the Operator Information Area (OIA). This line is always displayed from left to right. For the Hebrew environment, the following symbols have been added:
 

Understanding bidirectional Arabic support

The bidirectional Arabic support in VT enables the program to emulate an English/Arabic VT 220 display terminal. Special language and bidirectional functions are added to the list of standard functions supported by the emulation program.

Configuring a workstation
Understanding Arabic language and bidirectional functions
Summarizing bidirectional key combinations for Arabic
Understanding the Operator Information Area (OIA) in terminal emulation mode
 
 

Configuring a workstation

1. Right-click a VT configured session icon.
2. Click Properties.
3. Select ASMO-449 (7-bit) or ASMO-708 (8-bit) for the Host Code Page.
4. Click on the Screen tab and make sure that AVT3270 is the active font.

Understanding Arabic language and bidirectional functions

Language selection

The key combination Ctrl+N or Ctrl+L allows you to change the language layer. If the language layer is Latin, pressing Ctrl+N changes the language layer to Arabic. If the language layer is Arabic, pressing Ctrl+L changes the language layer to Latin.

 

Screen reverse

The key combination Ctrl+S reverses the screen image. If the screen orientation is left-to-right, pressing this key combination reverses the screen image to right-to-left. If the screen orientation is right-to-left, pressing this key combination reverses the screen image to left-to-right.
 

Column heading

Column heading mode causes blanks between columns of text to break insertions so the English titles to columns of data maintain their correct position. To enable the column heading mode, press the key combination Ctrl+C.

The following example illustrates the usefulness of the column heading.

When column heading is off:

Sent by host	Displayed by terminal (RTL screen)
PCs     Printers 200       40 500       90	PCs   Printers  40         200 90         500

When column heading is on:

Sent by host	Displayed by terminal (RTL screen)
PCs     Printers 200       40 500       90	Printers  PCs 40         200 90         500

 

Summarizing bidirectional key combinations for Arabic

Understanding the Operator Information Area (OIA) in terminal emulation mode

In the host session, the bottom line of the screen becomes an Operator Information Area (OIA). This line is always displayed from left to right. For the Arabic environment, the following symbols have been added:

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