Control Logic; Keyboard; Interconnection Cable; United States Standard Keyboard Arrangement - Texas Instruments 990 Installation And Operation Manual

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1.2.3.3 Control Logic. The control logic on the printed wiring board at the rear of the display
unit contains logic that supports the display function, provides an interface between keyboard
and VDT controller, and drives the audible alann.
1.2.4 KEYBOARD. A separate keyboard connects to the display unit by a 1.52-metre (5-foot)
cable. The four-mode keyboard provides the 128-character ASCII code set and additional eight-
bit codes for special functions. The Japanese keyboard has two additional modes for generating
the Katakana character set. A key on the Japanese keyboard selects alphanumeric or Katakana
character set. The key at the left of the space bar configures the Japanese keyboard for genera-
tion of the Katakana code set.
The 911 keyboard consists of a basic alphanumeric keyboard, numeric pad, cursor pad, and a
function key array. Figure 1-5 illustrates the United States keyboard arrangement. Key caps are
removable and may be replaced to provide custom legends for special applications such as inter-
national fonnats. (Refer to the appendixes for illustrations of international fonnats.)
1.2.5 INTERCONNECTION CABLE. The interconnection cable joins the display unit and the
VDT controller. The standard cable is 5 metres (16.4 feet) long and consists of coaxial cable for
video and seven signal lines (six conductors in balanced pair configuration and one single-ended
conductor). Optional cables are available to provide a maximum separation of 610 metres (2000
feet).
ERASE ERASE
FIELD INPUT
PRINT
f
REPEAT
-
' NS
CHAR
(8)134310
.. I
F2
F3 F4
FS F6 F7 FB CMD
SPACE
Figure 1-5. United States Standard Keyboard Arrangement
1-6
7
B 9
4 5
6
I
2 3
0
.
Digital Systems Division