Technical information
Congratulations for selecting this Radio Shack
Computer product!
The TRS-80 Expansion Interface greatly enhances
the
power
and usefulness
of
your
LEVEL
II TRS-80 Computer. With
it,
you
can
connect a wide variety
of
external components
("peripherals")
to
your
Computer - printers,
mass
storage
devices, communications equipment, voice synthesizers,
speech
recognition devices, custom-made I/O devices, etc.
Just
as
importantly,
the Expansion Interface lets you add
Random Access Memory,
so
your
System
can
hold longer
programs and process more data at once. Once you
have
filled
your
TRS-80
with
RAM
(16K), you
can
add either
16K
or
32K
to
the Expansion Interface,
for
a
total
of
either
32K
or
48K.
(1K
= 1024 memory locations
or
bytes.)
This
unit
is
shipped
with
no RAM
ch
ips installed and
it
has
Catalog Number 26-1140.
If
you
up-grade
your
Expansion
Interface
to
16K
RAM,
you'll
have
a 26-1141; and
if
you up-
grade
your
unit
to
the
full
32K
RAM,
you'll
have
a 26-1142.
Here's a
brief
description
of
the connections
your
Interface
provides:
• DIN jacks
for
two
Cassette Recorders -
to
let you
read
data
from
one
unit
and
write
to
the other
• Line Printer Card-Edge
for
connection
to
Radio Shack Line
Printers and
other
su
itable parallel interface printers
• Mini-Disk Card-Edge
for
connection
of
up
to
four
Radio Shack
Mini-Disk Drives
• Expansion Board Card-Edge
for
use
when
you
add the
RS-232-C Interface (or
other
custom-designed
PCB)
to
the
built-in expansion compartment
•
Bus
Card-Edge, which duplicates the signals present at the
TRS-80 Card-Edge.
In addition
to
allowing all these connections, the Expansion
Interface provides a 25
mS
heartbeat
interrupt
to
the Computer,
which you
can
use
to
provide
the
"tick"
for
a Real-Time clock
routine.
Notes:
Don't
connect
the
Expansion Interface
to
a
LEVE
L I
TRS-80. The
two
are
not
compatible.
This manual pertains
to
Expansion Interface
units
whose serial
numbers begin
with
035000
(for
26-1140), and
008000
(for
both 26-1141 and 26-1142).
© Copyright 1979
by
Radio Shack, A Division
of
Tandy Corporation, Ft. Worth,
TX
76102