Infoton VISTAR/GT User manual

VISTAR/GT
TECHNICAL USER'S MANUAL

GENERAL DESCRIPTION
The Infoton VISTAR / GT is a high-speed silent interactive
display terminal designed for use with an on -line computer
as a functional and operational replacement for a teletype -
writer . Incorporated into each VISTAR / GT is a keyboard,
video display, control and refresh electronics power supply
and both an RS - 232C and current loop interface. Operation
is in Roll Mode with data always being entered on the bot -
tom line.
DISPLAY CHARACTERISTICS
Characters/ Line
Lines/Display
Character Set
Character Format
Character Size
Cursor
Refresh Rate
Viewing Area
Color
Readability
Size
Weight
80
24
64 character ASCII (upper case)
5 x 7 dot matrix (upper case)
0.08" x .19" nominal
Non-destructive bl ink ing underscore
50 or 60 Hz
9" x 7"
White -P4 phosphor
Screen easily read without
disruptive reflections in 100
foot candle illumination
13" high, 19" wide, 23" long
35 pounds
Power 100
watts
105- 130 volt s, 60 Hz
105 - 130 volts or 210 - 260 volts, 50 Hz (Export Model)
Temperature 0° to 50 ° C (operating)
- 30 ° to 70 ° C (storage)
Humidity
o to 95 % non-condensing
MODE OF OPERATION
Full/Half Duplex
Full Duplex - Keyboard output to outgoing data line.
Display input from incoming data line.
Half Duplex - Keyboard output to display and to data
line. Display input from keyboard and data line.
Local/On-line
Local -Data line disconnected. Operation as in Half
Duplex.
On-Line -Data line connected.
Roll
Roll -When the format rolls up one line, the former
top line of display is lost; the bottom line is blank.
COMMAND FUNCTIONS
Erase Screen (Control L)
Line Feed, Carriage Return
Rub Out
Bell (70th character position)
INTERFACE
The VISTAR / GT provides both an EIA RS - 232C and a 20
or 60 milliampere current loop interface with START /STOP
character
format . Eleven internally generated, switch-
selectable transmission speeds and one externally controlled
speed are possible. Full duplex / half duplex operation and
parity generation are switch selectable. Transmits and
receives
10 or 11 bit code.
Switch-selectable data rates are
75, 110, 150 , 300, 600,
1200, 1800, 2400, 4800, 7200,9600 bits per second and
External. The External setting allows a data rate of up to
1800 characters per second. External timing is derived from
a TTL compatible pulse source at 16 times the data rate.

KEYBOARD
Layout - The VISTAR / GT keyboard layout is similar to that of a Model 35 KSR Teletype @.
Rollover - when one key is already depressed and a second key is then depressed, the code for the second key will not be
generated until the first key is released .
Repeat - when a code of function -generating key is depressed along with Repeat key, the code or function will be repeated
at a rate
of 10 per second.
I " .:# , 0 1 a , ( )
~
=10 HERE
I 2 3 4 5 6 7 8 9 0 . -
IS
.
WRU
TAPE +A-P-E- TAB
~
@
LIN E
ESC
Q w E R T y U 1 0 P
RET
FEED
X-OFF EaT RU
BELL
[ \ +
RUB
CTRL
REPT
BRK
A S 0 F G H J K L .
OUT
J
t ] < > ?
SH IFT Z X C V B N M / S HI FT
J .
SPACE BAR
CODE SET
The following codes are used as indicated in the VISTAR / GT .
Bits
Bits 7,6,5
4,3,2,1 000
001
010
011
100
101 110
111
r----- -,
0000 NULL
SPACE 0 @ P I @ P
0001 1 A Q I A Q
0010
2 B R I B R
I
0011 # 3 C S I C S
0100 $ 4 D T I D T
0101 % 5 E U I E U
0110
& 6 F V I F V
I
0111 BELL
7 G W I G W
1000
8 H X I H X
I
1001 9 Y I y
1010
LF
J Z J Z
1011 ESC + K K
1100
ERASE
< L \ L \
PAGE
1101 CR M M
1110
> N
""
N
""
? a a r--......J
1111 + I
RUB
L __ .....J OUT
The area enclosed by dashed lines represent lower case codes displayed as upper case characters.
The Rub Out code moves the cursor to the left one position .
C F 18 8 22
10 2(0 7S? IC 'I \0

INFOTON INCORPORATED • SECOND AVENUE, BURLINGTON, MASSACHUSETTS 01803 • AREA CODE 617 272·6660
SUBSIDIARY OF OPTICAL SCANNING CORPORA TION
Document No. 02421
June/1973
·VISTAR/GT
TECHNICAL USER'S MANUAL

INFOTON INCORPORATED • SECOND AVENUE, BURLINGTON, MASSACHUSETTS 01803 • AREA CODE 617 272·6660
SUBSIDIARY OF OPTICAL SCANNING CORPORATlON
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INFOTON INCORPORATED • SECOND AVENUE, BURLINGTON, MASSACHUSETTS 01803 • AREA CODE 617 272·6660
SUBSIDIARY OF OPTICAL SCANNING CORPORA TlON
INFOTON
TECHNICAL USER'S MANUAL
VISTAR/GT
TABLE OF CONTENTS
INTRODUCTION
SUMMARY OF CHARACTERISTICS
Interchangeability with Teletype@
Easy-to-Read Characters
High-Speed Transmission Rates
Choice of Computer Interface
Roll Mode
Transmission Mode
VISTAR/GT SPECIFICATIONS
Screen Format
Mechanical
Environmental
Controls, Switches and Connectors
Electrical
FUNCTIONAL DESCRIPTION
Local/On Line
Character Mode
OPERATIONAL FEATURES
Teletypewriter Compatibility
Cursor
Roll Mode
Response to Commands
Erase Screen
Bell
Carriage Return
Line Feed
Null
Break
Rubout
EQUIPMENT DESCRIPTION
Keyboard
Display
Control Logic
Controls
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@ Registered trademark of Teletype Corporation
iii

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7.
8.
9.
TABLE OF CONTENTS -Continued
INTERFACE
Introduction
Asynchronous Serial Interface
Wiring of Current Loop Interface
COMPATIBILITY WITH INFOTON VISTA
SERIES DISPLAY TERMINALS
OPERATING INSTRUCTIONS
Initial Setup
Establish Communication
Appendix A -
VISTAR/GT Code Set
Appendix B - VISTAR/GT Input-Output Codes
Appendix C - MUltipurpose Asynchronous Serial Interface
E IA Signals and Pin Connections
Appendix 0 - I/O Rates as a Function of Distance
LIST OF FIGURES
Figure 1-1. VISTAR/GT Display Terminal
Figure 6-1.
VISTAR/GT Keyboard
Figure 6-2.
Dot Matrix Character Format
Figure 6-3. Dot Matrix with Cursor
Figure 6-4. Location
of TV Controls on VISTAR/GT
Figure 7-1. VISTAR/GT Interface Panel
Figure 7-2. Wiring to VISTAR/GT Current Loop Terminal Strip
iv
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1. INTRODUCTION
Figure 1-1 VISTAR/GT* Display Terminal
The
INFOTON VISTAR/GT Display Terminal is an alphanumeric display designed for use with an
on-line computer as a high speed, silent, interactive terminal device. It can be utilized as a substitute
for a Teletype ® in an unbuffered (character-by-character) conversational mode. As a completely
self-contained desk-top
unit, the VISTAR/GT is ideally suited for high speed, two way data trans-
mission over common voice grade telephone lines. Incorporated
into each unit is a keyboard, power
supply, video presentation
control, refresh electronics and both an RS-232C and current loop inter-
face
for on-line connection to a dataphone, computer or teletype.
*Glass Teletypewriter
1

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2. SUMMARY OF CHARACTERISTICS
INTERCHANGEABILITY WITH TELETYPE®
TheVISTAR/GT can be substituted for a Model 33 or 35 Teletype® with no hardware or
software modifications. The VISTAR/GT can serve as an upgraded high speed terminal to
all time-sharing services using ASCII * Code regardless of the computer system used by the
service.
EASY-TO-READ CHARACTERS
High resolution, non-reflecting screen, and contrast-enhancing filter permit easy viewing at
distances up to 10 feet under direct glare and 100 foot-candle illumination.
HIGH-SPEED TRANSMISSION RATES
Eleven switch-selectable transmission rates from 75 to 9600 bits per second are provided.
CHOICE OF COMPUTER INTERFACE
The unit is supplied with two forms of asynchronous serial interfaces; i.e., a standard E IA
RS-232C interface and a 20 or 60 ma TTY style current loop.
ROLL MODE
The VISTAR/GT is operated in the Roll Mode with all data entering from the bottom line.
With each new line of data the screen presentation will roll up one line.
TRANSMISSION MODE
The VISTAR/GT is operated in a character-by-character transmission mode, exactly as a
Teletype®.
* American Standard Code for Information Interchange.
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3. VISTAR/GT SPECIFICATIONS
SCREEN FORMAT
Characters per line
Lines per display
Character set
Character format
Character size
Refresh rate
Viewing area
Color
Readability
MECHANICAL
Size
Weight
ENVIRONMENTAL
Operating temperature
Storage temperature
Humidity
80
24
64 character ASCII upper case
5 x 7 dot matrix
0.08 inch x 0.19 inch, nominal
50 Hz or 60 Hz
9 inches x 7 inches
Wh ite - P4 phosphor
Screen easily read without disruptive reflections in a
100-foot illumination.
13 inches high, 19 inches wide, 23 inches deep
35 pounds
0° to 50°C
-30° to 70°C
o to 95% non-condensing
CONTROLS, SWITCHES AND CONNECTORS
On/Off Switch
Local/On Line Switch
TV Intensity
TV Horizontal
TV Vertical
Data Rate Selector
Full/Half Duplex Switch
10/11 Bit Code Switch
Odd/Even/Mark Parity Switch
Current Loop Wiring Strip
EIA Connector
115/230 Volt Wiring Connections
50/60 Hz Refresh Switch
ELECTRICAL
Power consumption
Domestic power
Export power
STANDARDS
Underwriter's Laboratory
Front
Side Rear Internal
X
X X
X
X X
X
X
X
X
X X
X
100 watts
105 -130 volts; 60 Hz
105 - 130,210 - 260 volts; 50 Hz
Export models will conform to requirements established by British Post Office Telecommunications
Headquarters, the standards of the Verein Deutscher Elektrotechniker (VDE), and the Canadian
Standards Association (CSA).
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4. FUNCTIONAL DESCRIPTION
The VISTAR/GT Display Terminal is a completely self-contained desk top unit which can
be used as a plug-for-plug replacement for a Teletype@. The unit consists of a keyboard,
video monitor, refresh memory, control logic, and serial data interface. The modes of
operation and communications are described in the following paragraphs.
LOCAL/ON LINE
In LOCAL, the VISTAR/GT is disconnected from the data line but is functional in all other
respects. The LOCAL position is used only for demonstration and testing purposes. The
LOCAL/ON LINE selection is made by aswitch on the front panel of the terminal.
The remainder of this description refers to various types of ON LINE operation.
DATA FLOW
The keyboard communicates only to the interface transmitter, and only the interface
receiver communicates to the display memory. All transmissions are on a character-by-
character basis. All codes generated by the keyboard, including control or function codes,
go directly to the transmitter and then to the data lines.
The VIST AR/GT may be placed in full or half duplex. In half duplex, the interface receiver
is actuated in series with the transmitter, and transmitted codes are routed back through
the receiver and displayed. Control codes either perform their specific function (e.g., BE LL,
LINE FEE D, etc.) or are ignored.
In full duplex, the receiver is independent of the transmitter. Only data received from the
data line will appear on the display. As in half duplex, control codes either perform their
specific function or are ignored. In full duplex, therefore, information will be displayed
only if the computer at the end of the data line echoes back the information transmitted
from the keyboard.
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5. OPERATIONAL FEATURES
TELETYPEWR ITER COMPATI BI LITY
The VISTAR/GT reacts to the full ASCII character set (see Appendix A) receiving both
upper and lower case codes. The effect of each ASCII code on the VISTAR/GT is
shown in Appendix B. All characters are displayed as upper case characters. Lower case
characters received on the data line are stored in memory and are displayed as upper
case characters. Although the terminal may be programmed as a teletypewriter, the
full advantages of the VISTAR/GT as an interactive terminal are realized when the soft-
ware makes full use of the unit's features described in the following sections:
CURSOR
The cursor indicates the position at which the next data character will be displayed and
is always on the bottom line.
The cursor appears on the display screen as a blinking underscore, blinking approximately
five times a second. The blinking prevents the operator from losing track of the cursor.
The cursor will advance one step for each character that is typed. The Carriage Return,
Rub Out, and Line Feed codes also generate cursor movements.
The actual position of the cursor cannot be directly read by the computer. However)
since all cursor movements entered by the operator via the keyboard are transmitted to the
computer, the computer can at all times follow the position of the cursor. This feature
allows software editing on a page of textual data on the screen.
ROLL MODE
The VISTAR/GT is always in Roll Mode. When the screen fills, the data on the screen
rolls up one line; the former top line is lost and the bottom line is blank. As line after
line of text is written on the screen, the visual effect is that of a continuous scroll of text
moving past awindow.
Rolling is caused when a LINE FEED character is received by the terminal. Rolling is also
caused when the cursor is in the right corner of the screen and any displaying code including
SPACE is received.
The VISTAR/GT has been designed so that no restrictions are placed on the high speed
transfer of data in the roll mode. Data will not be lost even at 9600 bits per second.
RESPONSE TO COMMANDS
The VIST AR/GT terminal is controlled and manipulated from its data stream. The data
stream control logic is defined as follows:
1. Certain characters are designated as command characters (Appendix B).
2. The computer inserts these command characters within the text transm itted
to the VISTAR/GT.
3. The VISTAR/GT continually monitors the input data stream for these
command characters, performing a designated action upon reception of a
command character.
A description of the commands used to control the display follows.
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ERASE SCREEN
BELL
All data on the screen is erased. Cursor moves to first position of last line. This code is
generated from the keyboard by "Control L".
The bell will sound for the following conditions:
A. Receipt of the Bell Code (Control G) from the data line.
B. The movement of the cursor into the 70th position on a line.
CARRIAGE RETURN
Places the cursor in left-most position of the bottom line.
LINE FEED
NULL
Moves all data on the screen up one line. The cursor does not move.
No action is taken when this code appears on the data line. This code is generated from the
keyboard by "Control Shift P".
BREAK
Depressing the break key forces a "space" condition on the data line as long as the key is
depressed.
RUBOUT
Causes a rubout code (all one bits) to be transmitted. Cursor backspaces one position and'
no character enters memory.
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6. EQUIPMENT DESCRIPTION
The basic VISTAR/GT unit logically and physically consists of three parts; keyboard, display
and control. These components and the controls and indicators on the unit are described in
this section.
KEYBOARD
The operator interacts with the VISTAR/GT and the computer via the keyboard shown in
Figure 6-1.
LINE I ON
B .00,·8
LOCAL U OFF
SPACE BAR
Figure 6-1 VISTAR/GT Keyboard
The VISTAR/GT keyboard is composed of a set of 53 keys identical in placement to those
of a Model 35KSR Teletype@; a POWER ON/OFF switch and a LINE/LOCAL switch.
Appendix B illustrates the full code set, how to generate the codes from the keyboard, and
the effect of the codes on the display.
Both the SH I FT key and the CTRL (Control) key establish a mode for the keyboard; Le.,
data is not actually generated until a coded key is depressed. Depressing the SH I FT key in
conjunction with another key causes upper case characters to be transmitted. The keyboard
on the VISTAR/GT generates upper case codes for the alphabetic characters whether or not
the SHIFT key is depressed. The lower case codes are not generated by the VISTAR/GT
keyboard. For operator convenience, two SH IFT keys are on the keyboard. Each of these
keys has
the same effect on the data.
Control codes do not display on the screen, but in most applications are used as function
codes. Some of the control codes have been used as functions for the VIST AR/GT. For
example, Control L erases the screen.
The HERE IS key is inoperative since no answerback function is offered for the VISTAR/GT.
The REPEAT key when depressed in conjunction with a coded key or function key gen-
erates repeated transmission
of the code or function at a rate of 10 per second.
The BREAK key places "space"; i.e., a logical "0" condition, on the data line for as long
as the key is depressed.
7

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The keyboard has an interlock feature and a roll-over feature which govern operation when
two coded keys are simultaneously depressed.
When
one key is depressed and a second key is subsequently depressed, the code for the
second key will not be generated until the first key is released. No codes are generated
if
two or more keys are depressed simultaneously.
DISPLAY
The display screen is a cathode ray tube (CRT) with a P4 (white) phosphor. The viewing
area
of the display is 9 inches wide and 7 inches high. The screen format is 24 lines, each
80 characters long.
The displayed characters are white on a dark background. The characters are generated
on the display surface 50 or 60 times per second to provide flicker-free viewing. Characters
are displayed on the screen in a rectangular array (i.e., horizontal lines and vertical
columns). Each
of the possible character positions on the display consists of a 7 x 10
matrix. The 5 x 7 dot matrix format is illustrated in Figure 6-2 for the letters J and K.
The dot matrix forming the character is always in the upper left portion of the 7 x 10
matrix.
The position of the cursor within the 7 x 10 matrix is illustrated in Figure 6-3.
CONTROL LOGIC
The Control Logic contains the logic, power supply, central timing and control, refresh
memory, character generator, and communications interface. The most important functions
of the Control Logic are:
• Stores in a refresh memory all data received.
• Converts the ASCII characters into dot matrix form and presents them on the
CRT.
• Maintains
the display by refreshing the image at the rate of 50 to 60 times
per second.
• Provides the electrical interface between the electrical operating levels of the
VISTAR/GT and the equipment with which the terminal is operating. The
interface is described in detail in Section 7.
• Decodes command codes received on the data Iine and performs the appropriate
function.
8

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+ + + + +.+ + +.+ + + +.+ + +
+ + + + +.+ + +.+ + +.+ + + +
+ + + + +.+ + +.+ +.+ + + + +
+ + + + +.+ + +.+.+ + + + + +
+.+ + + +.+ + +.+ +.+ + + + +
+.+ + + +.+ + +.+ + +.+ + + +
+
+.+.+.+ + + +.+ + + +.+ + +
+++++++++++++++
+++++++++++++++
+++++++++++++++
+++++++++++++++
Figure 6-2 Dot Matrix Character Format
+ + + + + + + +.+ + + +.+ + +
+ + + + +:+ + +.+ + +.+ + + +
+ + + + +.+ + +.+ +.+ + + + +
+ + + + +.+ + +.+.+ + + + + +
+.+ + + +.+ + +.+ +.+ + + + +
+.+ + + +.+ + +.+ + +.+ + + +
+
+.+.+.+ + + +.+ + + +.+ + +
+++++++++++++++
+++++++++++++++
CURSOR~+ + + + + + + + + + + + + + +
+++++++++++++++
Figure 6-3 Dot Matrix with Cursor
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CONTROLS
The following two operator controls are located on the front panel in the plane of the
keyboard (See Figure 6-1):
• POWER ON/OFF Switch -In the OFF position, power is not connected to the
terminal. In the ON position the terminal is in the operating state. After the
switch is turned to ON, a 3D-second warm-up period is required. A light, built
into the switch, glows when the switch is in the ON position.
• LOCAL/LINE Switch -This switch determines whether the terminal is dis-
connected from the data line (LOCAL) or connected to the data line (LINE).
The three controls which govern the video presentation of characters are placed on the
side of the unit to the operator's left. The I NTENSITY knob permits the brightness of
the screen to be set for the operator's comfort. The HORZ and VERT controls allow
adjustment for a stable picture. They correspond to the controls normally found on a
commercial television receiver. Once these controls are set, they require infrequent
adjustment.
The placement of the video presentation controls is shown in Figure 6-4 below.
VERT HORZ
INTENSITY
L-HOLD~
Figure 6-4 Location of Video Presentation Controls on VISTAR/GT
(Side View of VISTAR/GT)
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7. INTERFACE
INTRODUCTION
The VISTAR/GT operates with a computer over either telephone lines (via a modem) or on
local connection by direct cable. The signal interface accommodates a wide range of
computer systems and a wide range of data rates. This has been accomplished by adhering
to commonly accepted standards for data transmission mode, transmission method
(asynchronous) and transmission rate. There are no restrictions imposed by data rate
limits upon any of the command codes of the VISTAR/GT. Thus cursor movement com-
mands, erase
commands, etc, may be executed at the maximum rate at which the terminal
can accept ordinary displaying codes. The Interface Modu Ie makes the necessary conversion
between
the electrical operating levels of the VISTAR/GT and those of the.e>,<ternal circuit
or computer with which the Interface Module is designed to operate. Also, the interface
arranges data in the format required by the circuit or computer.
ASYNCHRONOUS SERIAL INTERFACE
The VISTAR/GT communicates in a bit-serial, character asynchronous mode. The term
asynchronous is synonymous with START-STOP and implies that the receiver comes to
rest between characters. The STA RT bit allows the receiving device to initiate its timing
in proper synchronism with the incoming data. The STOP bit(s) ensure that the communi-
cation line is returned to the mark condition ready for a new START.
Transmitted data characters contain 10 or 11 bits, depending on the setting of a switch.
(The Model
33 and 35 Teletype@ terminals transmit 11-bit code.) In receiving, the VISTAR/
GT will operate with 10 or 11-bit formats. It is customary to use an 11-bit format at 110
bits per second or below, and 10 bits at higher speeds, but the VISTAR/GT is completely
flexible both in transmission and reception.
The following bit configuration and character structure is used by the Asynchronous
Interface:
Bit:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
START - "space" polarity -first bit transmitted
b 1 - least significant data bit
b 2 - data bit
b 3 - data bit
b 4 - data bit
b 5 - data bit
b 6 - data bit
b 7 - most significant data bit
Parity bit
STOP - "mark" polarity
STOP - "mark" polarity (note comments above on 11 th bit).
When
the interface is transmitting, it adds the start bit, computes and adds the parity bit,
and
adds the stop bit to every seven-bit code being sent. When it is receiving, it removes
the start and stop bits, and transfers only the seven information bits to the appropriate
logic.
When receiving, parity is checked. A code with incorrect parity is replaced by the question
mark (7) code and displayed as such.
Transmission
is always initiated with the start bit. Bits b 1 through b 7, shown above, bear
a one-to-one
correspondence with the bits b 1 through b 7 of the ASCII code (reference
Appendix B). The "Space" and the "Mark" polarities are as defined by the EIA Standard
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RS-232C.* Even parity implies that the total number of ones in every character should be
an even number; odd implies that it should be odd. Mark parity means that the parity bit
is always set to 1.
The mUltipurpose interface panel in the rear of the unit is shown in Figure 7-1. This
interface allows a user
to select a number of computer interfaces with anyone of a number
of data rates.
The interface panel shown in Figure 7-1 contains:
(a) Rotary Switch to Select Data Rate~
Th is switch has 12 positions -75, 110, 150, 300, 600, 1200, 1800, 2400, 4800, 7200,
9600 bits per second
and EXT. The EXT setting provides for handling data rates other
than the
11 fixed rates enumerated. The external clock must be a TTL compatible
pulse source cycling at 16 times the data rate (maximum data rate
is 1800 char/second).
RECEIVE RATE
1200 1800
PARITY
600 2400
300 4800
150 7200
FDX
HDX
75 EXT
CHAR
LENGTH
60 20 RET +
000
0
00
0 0 0
0 o 0
II I I I I I I I II
L--IN ----.J LOUT-.J
Figure 7-1 V 1ST AR/GT Interface Panel
EIA
* This is the accepted interface standard for serial data transmission which is adhered to by
the communication carriers. It was formed by the Electronic Industries Association and
issued as specification, RS-232. Version C is the current version of the specification.
12