SYSTEM OVERVIEW
The
Radio Shack TRS-80 Model
II
I Microcomputer
is
an
enhanced
version
of
Radio Shack's
popular
TRS-80
Microcom-
puter
(Model
I).
The
TRS-80
Model
III
is
software
compatible
with
the
Modell
so
that
owners
of
either system can
take
advantage
of
the
large
number
of
programs available.
Features
of
the
TRS-80 Model
III
which are
common
to
the
TRS-80 Model I include:
• Availability
of
Level I
or
Level
II
BASIC in
ROM
• Full size
typewriter
style keyboard
• A 12-inch video display
• Built-in cassette interface
• Character display
of
16
lines
of
64
characters
• Graphics
under
control
of
BASIC (128 H x
48
V)
• UL recognized
construction
In
addition,
the
Model
III
has
the
following standard features:
• 12-key
numeric
keypad
for
rapid
entry
of
numbers
• Rugged
cabinet
housing
keyboard,
electronics, video display, and power supply
• Direct drive video
monitor
for improved resolution
• Internal power supply
• Parallel
printer
port
for
use with Radio Shack printers
Several
other
features are available when Level
II
BASIC
is
used;
features such as: real
time
clock,
upper
and lower case
characters,
RAM
internally
expandable
to
48K
bytes,
I/O
port
for
peripheral
expansion,
and
cassette interface available
with
500
and
1500
baud rates.
Optional peripherals
for
the
TRS-80 Model
III
include disk drives (two built-in,
two
external)
with
double
density
for
increased storage
capacity,
and
a built-in RS-232 serial interface
for
communications
and peripheral interface.
The
Block Diagram shows
the
various internal
components
and
connections
of
the
Model
III
Microcomputer.
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