North Star Advantage User manual

·.·ADVANTAGE
Technical Manual
00464C

TABLE OF CONTENTS
Section
Page
1
INTRODUCTION
1-1
1.1
using this Manual
1-2
1.2 System Description
1-3
1.3 Warranty 1-6
1.4
ADVANTAGE Specifications
1-7
2 ADVANTAGE OPERATION
2-1
2.1
Operating Cont~ols
2-1
2.1.1
Keyboard
2-1
2.1.2
Rear Panel Controls
2-4
2.1.3
Diskette Loading/Unloading 2-6
2.2
System Startup
2-7'
2.2.1
Standard Startup - Booting
From Drive 1
2-7
2.2.2
Alternate Startup - Booting
From Drive 2
2-8
2.2.3 Alternate Startup -
Booting
From A Serial Port
2-8
2.2.4
Mini-Motor Startup
2-8
2.3 Restarting The System 2-9
2.3.1
Keyboard Reset 2-9
3
IMPLEMENTING ADVANTAGE FEATURES 3-1
3.1
Microprocessor Control 3-1
3.2 Memory Control 3-1
3.2.1
Memory Mapping
3-1
3.2.2 Memory
Parity 3-6
3.3
Inter'rupts 3-7
3.3.1
Maskable Interrupts 3-8
3.3.2
Non-Maskab1e Interrupts 3-8
3.4
Shared
I/O Interface Registers 3-9
ADVANTAGE
i
TECHNICAL MANUAL

TABLE OF CONTENTS
(continued)
Section Page
3.5.
Keyboard Control
3-16
3.5.1 Keyboard Reset Enable
3-16
3.5.2
Reset
3-17
3.5.3 Interrupt or Polled 3-17
3.5.4 Read Keyboard
3-19
3.5.5
Character Overrun 3-19
3.5.6 Cursor Lock 3-12
3.5.7
All Caps 3-21
3.5.8 Auto Repeat
3-21
3.6
Video
Display Control 3-22
3.6.1 Screen Mapping 3-23
3.6.2 Forming Letters
and Symbols
3-25
3.6.3 Display Flag
3-27
3.6.4 Screen Blanking
3-27
3.6.5 Video Driver 3-27
3.7 Floppy
Disk Drive Control
3-31
3.7.1 Power-on Initialization 3-34
3.7.2 Motor Enable 3-34
3.7.3
Drive Selection
3-34
3.7.4 Seek
3-34
3.7.5 Sector Selection 3-35
3.7.6 Read Data
3-36
3.7.7 Write Data
3-37
3.7.8
Floppy Disk Data Format
3-39
3.8
Hard Disk Drive Control 3-40
3.8.1
I/O Commands
3-40
3.8.2 Head Positioning
3-45
3.8.3
Data Format
3-47
3.8.4 Format Operation
3-48
3.8.5
Read Operations
3-49
3.8.6
Write Operation
3-50
3.9
Accessing The
I/O Boards
3-51
3.9.1
Reset
3-51
3.9.2 Board Identification
3-51
3.9.3 Byte Transfers
3-53
3.9.4
Interrupt
3-53
ADVANTAGE
ii
TECHNICAL MANUAL

TABLE OF CONTENTS (continued)
Section
3.10 SIO Board
3.10.1 Reset
3.10.2 Board Identification
3.10.3 Data Transfers
3.10.4 Control
3.10.5 Status
3.10.6 Interrupt or Polled
3.10.7 SIO In Asynchronous Mode
3.10.8 SIO In Synchronous Mode
3.11 PIO Board
3.11.1 Reset
3.11.2 Board Identification
3.11.3 Data Transfers
3.11.4 Control
3.11.5 Status
3.11.6 Interrupt or Polled
3.11.7 Programming Example
3.12 Speaker Control
3.13 Bootstrap Firmware
3.13.1 Startup
3.13.2 Boot From Disk Drive
3.12.3 Boot From Serial Port
4 THEORY OF OPERATION
4.1 Main PC Board
4.1.1
4.1.2
4.1.3
4.1.4
4.1.5
4.1.6
4.1.7
4.1.8
4.1.9
Central Processor
Main RAM
Boot PROM
Auxiliary Processor and
Keyboard
Floppy Disk Controller
Dislay RAM and Video Generator
I/O Board Interface
Speaker Circuit
Voltage Regulators
Page
3-54
3-54
3-54
3-55
3-55
3-57
3-58
3-58
3-66
3-72
3-72
3-73
3-73
3-73
3-74
3-75
3-77
3-77
3-78
3-78
3-79
3-82
4-1
4-1
4-4
4-15
4-18
4-18
4-22
4-25
4-36
4-41
4-41
4.2 Hard Disk Controller Board 4-44
ADVANTAGE iii TECHNICAL MANUAL

TABLE OF CONTENTS (continued)
Section
Page
7
ADVANTAGE
4.2.1
4.2.2
4.2.3
Track and Sector Format
Hard Disk Controller
Hard Disk Drive
5 PREVENTIVE MAINTENANCE
4-44
4-44
4-55
5-1
5.1 Wear and Damage Inspection 5-2
5.2 Voltage Checks and Adjustment 5-3
5.3 Voltage Controlled Oscillator Check
and Adjustment 5-4
6 DIAGNOSTICS
6.1 The Mini-Monitor
6.2 The General Diagnostic Programs
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
Single Block Mode
Floppy Disk Subsystem Test
Executable Memory Test
Video Memory Test
SIO Board Test
Keyboard Test
Display Monitor Test
6.3 Hard Disk Diagnostic Procedures
TROUBLESHOOTING AND REPAIR
7.1 Tools and Test Equipment
7.2 Troubleshooting Procedures
7.2.1 Troubleshooting Chart
7.3 Assembly Replacement Procedures
7.3.1 Opening and Closing ADVANTAGE
6-1
6-2
6-4
6-4
6-6
6-8
6-11
6-12
6-13
6-22
6"';23
?,-l
7-1
7-2
7-2
7-15
Cabinet 7-16
7.3.2 Removing and Installing The
Keyboard 7-20
7.3.3 Removing and Installing The
Main
PC Board 7-24
7.3.4 Removing and Installing a
Disk Drive 7-27
iv
TECHNICAL MANUAL

ADVANTAGE
Aggendix
A
B
C
o
E
F
G
H
I
J
TABLE OF CONTENTS (continued)
CHARACTER CODE TABLES
IIO ADDRESS SUMMARY
PC BOARD JUMPERS
ERROR MESSAGES
PARTS LISTS
FULL ASSEMBLY DRAWINGS
Z80 MICROPROCESSOR DATA SHEET
8251 USART DATA SHEET
SCHEMATICS
READER RESPONSE FORM
~
A-I
B-1
C-l
0-1
E-l
F-l
G-l
H-l
I-I
J-l
vi TECHNICAL MANUAL

Figure
1-1
1-2
2-1
2-2
2-3
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
ADVANTAGE
ILLUSTRATIONS
The ADVANTAGE Computer
Functional Block Diagram
The ADVANTAGE Keyboard
ADVANTAGE Rear View
Loading a Diskette
Memory Mapping Registers
The Three Shared I/O Interface Registers
Data Format In Display RAM
Disk Read/Write Timing
Floppy Disk Track and Sector Format
Hard Disk Track and Sector Format
Asynchronous Modem'Configuration Header
Asynchronous Terminal Configuration Header
Current Loop Configuration Header
Current Loop Circuit
Buffer Full Modification
Synchronous Modem Clock Header
Synchronous Modem Configuration Header
Synchronous Terminal Clock Header
Synchronous Terminal Configuration Header
Standard PIO Configuration Header
The ADVANTAGE System Block Diagram
Central Processor Block Diagram
Main RAM Block Diagram
Main
RAM Timing
Auxilliary Processor Block Diagram
Disk Controller Block Diagram
Display RAM and Video Driver
Horizontal Scan Timing
Vertical Scan Timing
I/O Board Interface Block Diagram
I/O Board Timing
Voltage Regulators Block Diagram
Hard Disk Controller Block Diagram
SIO Board Block Diagram
Connector Pin Assignments (Asynchronous)
SIO Connector Pin Assignments (Synchronous)
PIO Board Block Diagram
PIO Connector Pin Assignments
Standard PIO Configuration Header
PIO Port Timing
~
1-1
1-5
2-1
2-4
2-6
3-3
3-10
3-24
3-38
3-39
3-47
3-59
3-60
3-61
3-62
'
3-63
3-66
3-66
3-67
3-67
3-72
4-2
4-5
4-15
4-17
4-19
4-22
4-26
4-31
4-35
4-36
4-40
4-42
4-45
4-58
4-60
4-60
4-63
4-65
4-66
4-68
vii
TECHNICAL MANUAL

Figure
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-10
7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9
7-10
7-11
7-12
7-13
7-14
7-15
7-16
7-17
7-18
7-19
7-20
7-21
7-22
ADVANTAGE
ILLUSTRATIONS (continued)
Single Block Mode - Display Format
Floppy Disk Subsystem Test - Display Format
Executable Memory Test - Display Format
Locating a Defective Main RAM Chip
Loacating a Defective Video RAM Chip
SIO Board Test - Display Format
Keyboard Test Modules and Sections
N-Key Rollover Test
Keyboard Test Summary
Display Format for Display Monitor Test
ADVANTAGE Troubleshooting Chart
Pin Locations on the Disk Drive
Pin Locations on the Controller Board
(Solder Side)
Power Cord Removal
Bottom View of the ADVANTAGE
Cabinet Separation Sequence
Major Components Inside the ADVANTAGE
ADVANTAGE 20 Base Assembly
ADVANTAGE HD-5 Base Assembly
ADVANTAGE 20 Cable Connections
ADVANTAGE 80-5 Cable Connections
Main PC Board Removal
Disk Drive Shield Removal
Disk Drive Cabling
Upper Disk Drive Removed
Power
Supply Components
Cover Assembly
Fan Cable Removal/Installation
Video Components
Video PC Board
CRT Removal
CRT Installation
~
6-5
6-7
6-9
6-10
6-11
6-12
6-14
6-19
6-20
6-22
7-1
7-11
7-13
7-16
7-17
7-18
7-19
7-20
7-21
7-22
7-23
7-25
7-27
7-28
7-29
7-30
7-32
7-32
7-34
7-35
7-36
7-38
viii TECHNICAL MANUAL

Table
1-1
2-1
2-2
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-17
3-18
3-19
3-20
3-21
3-22
3-23
3-24
3-25
3-26
3-27
3-28
3-29
3-30
3-31
·3-22
3-33
4-1
4-2
4-3
4-4
4-5
4-6
4-7
ADVANTAGE
ILLUSTRATIONS (continued)
ADVANTAGE Specifications
ADVANTAGE Keys
Rear Panel. Controls
256K Address Space Allocation
Memory Mapping I/O Addresses
Memory Mapping Register Configurations
Memory Parity I/O Address
Memory Parity Status and Control Bytes
Shared Register Addresses
I/O Control Register Format
I/O Commands for I/O Control Register
I/O Status Register 1 Format
I/O Status Register 2 Format
Sample Routine for Reading Characters
Video I/O Addresses
Video Driver Control Codes
Video Driver Data Block Format
Floppy Disk I/O Addresses
Floppy Drive Control Register Format
Hard Disk Drive I/O Commands
Hard Disk Drive Control Register Format
Hard Disk Controller/Drive Status Bits
I/O Board Addresses
I/O Board Identification Codes
First Digit of I/O Addresses
SIO Interrupt Mask Format
Serial I/O Addresses
Asynchronous Baud Rate Selection
Sample Asynchronous I/O· Routines for SID
Board
Synchronous Baud Rate Selection
Sample Synchronous I/O Routines for SIO
Board
PIO Interrup Mask Format
PIO Status Byte Format
Parallel I/O Addresses
Sample Routine for Outputting PIO Data
Boot PROM CRC Routine
I/O Status Register 1 Format
I/O Address Decoder Signals
I/O Select PROM Summary
I/O Control Register Format
I/O Commands
I/O Status Register 2 Format
Floppy Disk I/O Instructions
~
1-7
2-2
2-5
3-2
3-4
3-5
3-6
3-7
3-9
3-11
3-12
3-14
3-15
3-20
3-26
3-28
3-29
3-31
3-33
3-41
3-43
3-44
3-52
3-52
3-55
3-56
3-57
3-64
3-65
3-68
3-69
3-74
3-75
3-76
3-77
3-81
4-8
4-9
4-10
4-12
4-13
4-20
4-23
ix
TECHNICAL MANUAL

Figure
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
5-1
6-1
6-2
6-3
7-1
7-2
7-3
7-4
ADVANTAGE
ILLUSTRATIONS (continued)
Floppy Disk Control Register Format
HTIML Horizontal Scan PROM
HTIMH Horizontal Scan PROM
60 Hz vertical Timing PROM
50 Hz Vertical Timing PROM
1/0 Board Pin Assignments
Hard Disk Controller Input/Output Sign~ls
SIO Board I/O Instructions
SIO Board 1/0 Instructions
PIa Board 1/0 Instructions
PIa status Byte Format
PIa Interrupt Mask Format
Preventive Maintenance Schedule
Mini-Monitor Commands
Keyboard Test Abbreviation Codes
Keyboard Test Control Keys
Main
Board Input Power (Jll)
Main Board Video Interface (J7)
Main Board - Floppy Disk Power (JI0)
Driver Status Signals
4-24
4-28
4-29
4-33
4-34
4-38
4-46
4-61
4-62
4-67
4-68
4-69
5-1
6-3
6-16
6-21
7-6
7-6
7-10
7-14
x
TECHNICAL MANUAL

1.2 SYSTEM DESCRIPTION
The North Star ADVANTAGE is packaged in a molded high
impact plastic unit with an integral keyboard. The
keyboard features an ASCII typewriter-like layout with
programmable function keys and a numeric keypad.
The ADV~TAGE cabinet holds the l2-inch (diagonal)
monitor, video circuit assembly, and main processor
board which contains the CPU, the memory, the floppy
disk controller, the I/O interface circuits, and the
power supply regulator. The cabinet also houses either
two floppy disk drives or one floppy disk drive and one
5" Winchester hard disk drive.
The ADVANTAGE uses a 4 MHz Z80A microprocessor as the
cpu. 64 Kbyte of 200 nsec dynamic random access memory
(RAM) is provided for program storage, with a separate
20 Kbyte 200 nsec RAM for the bit-mapped display. A 2
Kbyte PROM contains the resident bootstrap program. An
auxiliary 8035 microprocessor controls keyboard and:
disk input/output (I/O) to and from the cpu.
The display can operate as a 1920 character display
with 24 lines x 80 characters or as a bit-mapped
display with 240 x 640 pixels. Each pixel is
controlled by one bit in the 20 Kbyte display memory.
The
n-key rollover keyboard contains 49 standard
typewriter keys, 9 symbol or control keys, a l4-key
numeric/cursor control pad, and 15 programmable
function keys.
In the ADVANTAGE 2Q, the two integral 5-1/4" floppy
disk drives are quad capacity double-sided and double-
density to provide 360 Kbyte of storage per diskette.
In the ADVANTAGE HD-5, the Winchester hard disk drive
provides 5 Mbytes of storage.
ADVANTAGE
1-3
TECHNICAL MANUAL

A simplified block diagram of the ADVANTAGE computer is
shown in Figure 1-2. The blocks are described briefly
below. Refer to Chapter 4, Theory of Operation for
more detailed descriptions of ADVANTAGE component
blocks.
-The Central Control Unit maintains primary control of
the system. Contained herein are the Z80 and 8035
processors and the controllers for the I/O devices.
-The 64K Main RAM (Random Accesp Memory) provides
temporary storage of programs and data. Programs are
executed while residing in this RAM.
-The 2K Boot PROM (Programmable Read-Only Memory)
provides bootstrapping and a built-in Mini-Monitor
for debugging functions.
-The Video Monitor and 20K Display RAM produce a high
resolution display that can be used for graphics
applications, or to display messages for the
operator.
-The floppy Disk Drive(s) use 5-1/4 inch quad capacity
diskettes. The optional hard Disk Drive replaces the
second floppy drive.
-The Speaker produces a tone used to signal the
operator. The frequency and dUration of the tone
are under program control.
-The Keyboard
configuration,
function keys.
includes the standard typewriter
a numeric keypad and 15 programmable
-The I/O Board Slots allow the ADVANTAGE to be
customized for specific applications. There are six
board slots which may contain interface boards for
external devices or other boards which expand the
computing power of the ADVANTAGE. Two types of North
Star boards are presently available for use in this
area: the Serial Input/Output (SIO) Board and the
Parallel Input/Output (PIO) Board. As supplied, the
ADVANTAGE contains an SIO board installed in I/O
slot one.In an ADVANTAGE HD-5 the Hard Disk
Controller resides in I/O slot six.
ADVANTAGE 1-4 TECHNICAL MANUAL

64K
MAIN
RAM
2K
BOOT
PROM
SPEAKER
I·
ADVANTAGE
Functional Block Diagram
VIDEO
MONITOR
20K
DISPLAY
RAM
CENTRAL
CONTROL
UNIT
KEYBOARD
---
Figure 1-2
FLOPPY DISK
DRIVE 1
FLOPPY DISK
DRIVE 2
I/O BOARD
SLOTS
..
;>
~
7
EXTERNAL
I/O
DEVICES
r------------.
I I
I I
I HD-5 I
or
I I
I HARD DISK I
I I
I I
'------r----.J
I
1-5
TECHNICAL MANUAL

1.4 ADVANTAGE SPECIFICATIONS
Table 1-1 lists the physical
characteristics of the ADVANTAGE.
Table 1-1
ADVANTAGE Specifications
CABINET
and
electrical
Dimensions
48 cm wide x 51 cm long x 31.5 cm high
(18-3/4 in x 20 in x 12-112 in)
Net Weight
19.5 kg (43 lbs)
Composition
High impact structural foam
POWER REQUIREMENTS
External (with
Internal Line Filter)
Domestic 115 VAC, (98 to 132 VAC)
60Hz
International 230 VAC, (196 to 264 VAC)
50/60 Hz
Internal Supply ±5 VDC ±5%
Voltages +12 VDC ±5%
Power
Consumption
2 amps @ ll5V
1 amp @ 230V
TEMPERATURE AND HUMIDITY
Operating: 10 C to 40 C
(with diskette) (50 F to 104 F)
20% to 80% non-condensing
Non-operating -40 C to 60 C
(-40 F to 140 F)
ADVANTAGE
1-7
TECHNICAL MANUAL

Shipping
Table 1-1 (continued)
-40Cto52C
(-40 F to 125 F)
5% to 95% non-condensing
PROCESSOR/MEMORY
CPU
Memory
VIDEO
Screen
Grid
Graphics
resolution
Refresh rate
CRT Anode
Voltage
KEYBOARD
Key tops
Z80A Microprocessor, operating speed: 4MHz
8035 auxiliary processor for keyboard and disk
64K byte Main RAM
20K byte Display RAM
2K byte Boot PROM
28 cm (12 in) diagonal
P31 phosphor (green)
High impact, non-glare safety shield
1920 character display,
24 lines by 80 characters
5X7 character in 8xlO dot matrix
240 pixel high x 640 pixel wide
60 Hz
17 KV maximum
Sculptured
Selectric-compatible
N-Key roll-over for fast data entry
Number of Keys: 87
Key Groups
ADVANTAGE
49 Standard Typewriter Keys
l4-key Numeric Pad with ENTER key
15 Programmable Function Keys
9
Additional Symbol/Control Keys
1-8
TECHNICAL MANUAL

Table 1-1 (continued)
Other features Full Cursor control
Special Shift-Lock Keys
5
Shift Modes
Auto
Repeat
FLOPPY DISK DRIVES
Number of
drives
Two floppy disk drives housed in cabinet
Diskettes
Standard 5-1/4 in floppy diskettes.
Recommended type: Dysan part No. 107/2D.
512 bytes/sector, 10 (hard) sectors/ track
35 tracks/side, 2 sides/diskette
storage
.Quad (double-sided, double-density)
360K bytes per diskette (formatted)
Transfer Rate 250K bits/second
Latency 100 ms
(average)
Access Time
Track-to-Track 5 ms
Track Density 48 tpi
Tracks per Side
35
ERROR RATES
Soft errors 1 per
108bits
Hard errors 1 per
l011bi ts
Seek errors
1
per 106 seeks
read
read
Disk speed
300 rpm + 3.0%
ADVANTAGE
1-9 TECHNICAL MANUAL

Table 1-1 <Continued)
HARD DISK DRIVE
Capacity
Unformatted
Per Drive
Per Surface
Per Track
Formatted
Per drive
Per surface
Per track
Per sector
Sectors per track
Transfer Rate
Access Time
Track to track
Average
Maximum
Settling time
Average Latency
Rotational Speed
Recording Density
Flux Density
Track Density
Cylinders
Tracks
R/w Heads
Disks
Max Error Rates:
Soft read errors =
Hard read errors =
Seek errors =
6.38 megabytes
1.59 megabytes
10416 bytes
5.0 megabytes
1.25 megabytes
8192 bytes
512 bytes
16
5.0 megabits per
second
3 ms
170 ms
.500 ms
15 ms
8.33 ms
3600 rpm ± 1%
7690 bpi max
7690 fci
255 tpi
153
612
4
2
1 per 109 bits read
1 per 10
11
bi ts read
1 per 106 seeks
Less bad spots, if any (max 16)
Not recoverable within 16 retries.
ADVANTAGE
1-10
TECHNICAL MANUAL

INPUT/OUTPUT
I/O Bus
Serial I/O
(SIO)
Parallel I/O
ADVANTAGE
Table 1-1 (continued)
Slots for up to six plug-in boards (up to five
plug-in boards in the HD-5)
Each board addressed by 16 I/O addresses
RS232 Serial Port
Current loop option
Asynchronous: 45 baud to 19.2 kilobaud
Synchronous: 2400 baud to 51 kilobaud
8-bit data in and out with three handshake lines
for each port
Maximum speed is limited by the processor.
1-11
TECHNICAL MANUAL

ADVANTAGE OPERATION 2
This chapter describes startup and general operation of
the ADVANTAGE. It contains a description of the
keyboard and rear panel controls of the ADVANTAGE. It
also provides instructions for loading diskettes in the
floppy drive(s), booting a program, and methods for
performing a system reset.
2.1 OPERATING CONTROLS
2.1.1
The ADVANTAGE operating controls consist of the
keyboard and rear panel controls. On the rear panel
are a power switch, screen brightness control, and the
system Reset button. For operation of the disk drives,
diskette loading and unloading procedures are given.
Keyboard
Primary system control is maintained by entering
commands and data from the ADVANTAGE keyboard. The
keyboard is illustrated in Figure 2-1. There are 87
keys, described in Table 2-1. The keys generate
standard ASCJI codes as well as additional 8-bit hex
codes. Keys and their codes are listed under various
tabu1~tions in Appendix A.
Characters entered from the keyboard are displayed
on the CRT screen under program control. A program-
maintained cursor marks the position on the screen
where the next character entry will be displayed.
The ADVANTAGE Keyboard
Figure 2-1
ADVANTAGE 2-1 TECHNICAL MANUAL

Key Group
CHARACTER
KEYBOARD
CONTROL
CURSOR
CONTROL
ADVANTAGE
Keys
ABCDEFGHIJKLM
NOPQRSTUVWXYZ
l234567890! @#
$%A&*() __ =+;:
'",.<>I?[]{}
(space)
SHIFT
ALL CAPS
RETURN
TAB
<X]
ENTER
8 direction
arrows
CURSOR LOCK
Table 2-1
ADVANTAGE Keys
2-2
Description
Alphabetic, numeric, and special
symbols. Numbers and three
symbols (.,-) are also available
on the numeric~pad.
Either of two identical keys
which cause most of the other
keys to shift into upper case
(see Appendix A).
Shifts only alphabetic
characters to upper case. Key
is a "push on-off" type with
LED to signal when function
is active.'
Carriage return.
Position to next tab set on the
line. Setting and releasing tabs
is done under program control.
Character delete, backspace, qr
delete and backspace depending
upon the program being used.
Numeric pad data entry key.
All cursor activity is under
program control.
Shifts only cursor control keys
(1-9 on numeric pad) to allow
cursor positioning without using
SHIFT key. Key is a "push on-
push off" type with LED to
signal when key is active.
TECHNICAL MANUAL