Texas Instruments 990 Installation And Operation Manual page 99

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945423-9701
APPENDIX G
MODEL 911 ARABIC DISPLAY TERMINAL
G.l GENERAL
This appendix provides details of the keyboard and display interface of the Model 911 Arabic video
display terminal (VDT). Recommendations are also provided in this appendix for users who wish to
develop their own device service routine (DSR) to control the Arabic terminal.
The Texas Instruments Model 911 Arabic VDT is designed specially to meet the requirements of
both the Arabic and Latin-based languages. The terminal can be programmed to handle the natural
writing directions of the languages and to perform the character shaping required to faithfully repre-
sent Arabic script. This appendix describes the keyboard and VDT interfaces provided by the Model
911 Arabic VDT.
G.2 KEYBOARD
The standard keyboard consists of 91 keys grouped as shown in figure G-!. The standard keyboard
layout is organized into four types of keys:
• Data entry keys
• Cursor control and edit keys
• Numeric keys
• Special function keys (Fl - F8)
The keyboard produces an 8-bit code for all keys except for the control keys REPEAT, ARABIC
( 4.S!
~
),
LATIN, SHIFT, CONTROL and UPPERCASE LOCK.
The REPEAT key provides a repeat code function so that the same key can be entered several times.
To repeat a key code, hold down the REPEAT key while pressing the key to be repeated. The key
code entered is repeated at a frequency of 10 characters per second.
F,
I
F2
I
F3
I
F4
I
F5
I
F6
I
F7
I
Fa CMO
ERASE ERASE
FIELD INPUT
7
V
a A
9 ..
PRINT
I
REPEAT
4
t
5 0
6 "\
-
HOME
-
,
,
2 "(
3~
INS
j
DEL
CHAR
CHAR
0
Figure G-l. Arabic 911 Keyboard
The ARABIC (
4.S!
~
),
LATIN, SHIFT, CONTROL and UPPERCASE LOCK control keys
determine the character set generated by the keyboard, i.e., the specific codes generated by the other
keys on the keyboard. When the ARABIC key is pressed, a warning lamp is lit next to the key.
G-l
Digital Systems Division