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4
TECHNICAL ASPECTS ________________________________________ _
HOW IS THE 820-11 DESIGNED?
BASIC CONCEPT
The 820-11 system is designed to provide maximum versatility. This is accomplished by minimum use of
fixed functions and maximum use of user selected functions. This approach to system design provides a
"today" computer that has the capability to make maximum use of tomorrow's software. Xerox is committed
to meeting the customer's future needs by providing expanded software packages, upward compatability
with other Xerox products and standard interface with the Xerox local communications network-ETHER-
NET.
"
HARDWARE DESIGN
The heart of the 820-11 system is a 64K random access memory (RAM) Z80-A microprocessor driven at a
clock speed of 4MHz, with a switch able 6K Read Only Memory (ROM). The 6K ROM unit is switched into
the system at startup to provide the system with the basic ability to load the user selected functions into the
central processor unit (CPU). Only seconds after turn-on, the 820-11 CPU is performing the user defined
tasks. At the touch of a key the 820-11 converts from an electric typewriter to a powerful word processor or
any of the many scientific processing systems available today. And tomorrow, the 820-11 will be as
up-to-date as the latest software; because the functions of the 820-11 are completely controlled by user
selected software.
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SPECIFICATIONS
Display Screen: 24 lines, 80 characters
per line displayed white on black background,
with brightness control.
Keyboard: Separate unit from Display
Screen.
Printer Speed (40 CPS): Up to 40 characters per
second, . bi-directional.
Writing Line: 13" standard
Platen: 14.5" standard
Ribbon Cartridges: Interchangeable film
or fabric.
Printer Speed (25 CPS): Up to 25 characters per
second, bi-directional
Writing Line: 13.2" standard
Platen: 14.5" standard
Ribbon Cartridges: Interchangeable film
Size & Weight
Display Unit:
Keyboard:
Disk Unit (51/4"):
Height 12.87", Width 14.5", Depth 13.5"
Weight 30 Ibs.
Height 3.75", Width 20", Depth 9.5"
Weight 10 Ibs.
Height 6.7", Width 8", Depth 9"
Weight 10 Ibs.
Disk Unit (8" Floppy): Height 10.75", Width 14", Depth 17.5"
Weight 48 Ibs.
Disk Unit (8" Rigid): Height 10.75", Width 15.5", Depth 17.5"
Weight 54 Ibs.
Printer (40 CPS):
Height 8.5", Width 24.5", Depth 19"
Weight 56 Ibs.
Printer (20 CPS):
Height 9.25", Width 24.25", Depth 17.75"
Weight 50 Ibs.
Disk Storage Capacity:
51/4" Floppy (double density)
155K formatted (78 pages approx.) per drive, per side
8" Floppy (double density)
482K formatted (241 pages approx.) per drive, per side
8" Rigid (10 mb)
8.192 Mb formatted per drive
Electrical Requirements:
System Voltage:
90-132 VAC single phase
(two wires plus ground)
Frequency:
59.5-60.5 Hz
Current:
One Display (Controller, Display, Keyboard
and Printer) can be connected to a 15 amp
circuit.
Amps:
System with 51/4"
Disk Drive
1.5 amps
System with 8"
Disk Drive
3 amps
Xerox Printer
2 amps
Environmental Requirements:
Operating:
50° to 90° F
20% to 80%, humidity
Non-operating:
- 20° to 150
0
F
1.5% to 90%, humidity
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