Table of Contents
Advertisement
configurations, the indicator being on signifies that the
6.3.1 Types of Keyboards
channel 'operational out' tag line is active.
6.2.1.2 INSERT MODE Indicator
This indicator is displayed at character row 6 on Model 1
display stations and at character row 12 on Model 2 display
stations. The indicator lights when the INSERT MODE key
on the keyboard is pressed. It signifies that the display
station is in the Insert mode of operation. The indicator
remains on, and the display station remains in Insert mode
until the RESET key is pressed.
6.2.1.3 INPUT INHIBITED Indicator
This indicator is displayed at character row 8 on Model 1
display stations and at character row 14 on Model 2 display
stations. The lighted indicator signifies that manual input to
the display station from the keyboard, selector light pen,
and Operator Identification Card Reader is blocked. The
indicator is extinguished by program control or by pressing
the RESET key. When the security key lock is off, this
indicator lights.
6.2.2 Internal Indicator (SWEEP INDIC)
The SWEEP INDIC indicator is a neon bulb mounted on
the display station analog card. The lighted indicator
signifies that the horizontal deflection circuits are oper-
ating.
6.2.3 Arc-Suppression Neon
The
a~c-suppression
neon is located on the arc-suppression
board in Model 1 display stations and on the voltage
distribution board in Model 2 display stations. It is not an
indicator and will never be seen lighted. The two elements
of the neon bu Ib are connected between de ground (R ET)
and the display station frame ground. The neon acts as a
momentary short circuit whenever the difference in poten-
tial between its two elements would have exceeded approx.i-
mately 90V. The difference in potential is occasionally
generated by the inherent characteristic of a cathode-ray
tube to arc. Arcing causes transients in the return path of
the tube. Restricting potentials to 90V to ground protects
display station circuitry from possible damage.
6.3 KEYBOARDS (Optional Feature)
Four keyboards are used with 321"1 Display Stations.
Keyboards of the same type are interchangeable among
display stations having keyboard adapter circuitry installed.
EBCDIC is the basic code used on all keyboards.
6.3.1. 1 Typewriter Keyboard
The typewriter keyboard uses a standard typewriter key
layout of 66 keys. An additional 12 Program Function keys
may
be
incorporated in the standard typewriter keyboard.
Diagram 6-2 illustrates the typewriter keyboard.
6.3.1.2 Operator Console Keyboard
The operator console keyboard uses an IBM 1052-7 type
key layout with an additional 12 Program Function keys.
Diagram 6-3 illustrates the operator console keyboard.
6.3.1.3 Data Entry Keyboards
The two data entry keyboards use 66 keys, consisting of 36
alphameric keys and 30 control keys. Diagram 6-4 illus-
trates the two data entry keyboards.
6.3.2 EBCDIC Keyboard Codes
The EBCDIC code is the standard code used with all 3270
system keyboards. Diagram 6·5, sheet 1, shows the key-
board codes for the typewriter and operator console
keyboards. Characters (and functions) are shown in the
Graphics column as they appear on typewriter keyboard
key tops. The operator console keyboard key layout is
similar. Sheet 2 shows the EBCDIC code arrangement used
on the data entry keyboard(s). Diagrams 6-6 and 6-7 show
the codes for unique ASCI I and WTC language characters.
6.4 ASCII OPTIONS
ASCII* character generator and keyboard options may
be
present on 3277 Display Stations. ASCII options are
available only in the United States and Canada. The
following paragraphs describe the characteristics of these
options.
6.4.1 ASCII Character Generators (Optional Features)
Two ASCII character generator options allow the ASCII
code set to be displayed. The ASCII code set includes the
symbols [, ], \ , and "which are not used in the 3277
EBCDIC code set. ASCII option A uses the symbols I and
-', while option B substitutes the symbols
!
and
1\
respectively. Each option requires a different character
-ASCII American National Standard Code for Information Inter-
change, X3.4-1968.
Reference Data
6·3
Advertisement
Table of Contents
