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[Illustration: Radio Shack

TRS-80

EXPANSION
INTERFACE]




Radio Shack

TRS-80

EXPANSION
INTERFACE

_SEE CAUTION INSIDE COVER_

Catalog Numbers 26-1140
                26-1141
                26-1142

=Operator's Manual=

CUSTOM MANUFACTURED IN U.S.A. FOR RADIO SHACK [TC] A DIVISION OF TANDY CORPORATION




INTRODUCTION


The TRS-80 Expansion Interface (see Figure 1) consists of the Case, a
DC Power Supply, a Ribbon Cable, a Cassette Recorder Jumper Cable and
an additional Cassette Recorder Cable for Cassette Recorder number 2.
Notice that the DC Power Supply is not installed in the Case upon
receipt. It must be installed using the procedures under the heading
"SETTING UP" and as illustrated in Figure 2.

The Case houses the Expansion Interface Printed Circuit Board (PCB),
two DC Power Supplies and provides a housing area for an additional
expansion PCB. The Expansion Interface utilizes a real-time clock and
contains sockets for the addition of up to 32K of RAM in 16K
increments.

One DC Power Supply provides power to the PCB. The other one supplies
power to the TRS-80. The Power Supplies are interchangeable.

The ribbon cable has 40-pin connectors on both ends and is used to
connect the Expansion Interface to the TRS-80. You received hoods for
these connectors which are covered later in this manual.

The Cassette Recorder Jumper Cable has 5-pin audio DIN connectors on
both ends. It connects between the Expansion Interface Tape
input/output (I/O) and the TAPE connector on the right rear of the
TRS-80 Microcomputer.

The Cassette Recorder Cable is provided to connect the Expansion
Interface to Cassette Recorder number 2.


CAPABILITIES AND ADVANTAGES

The Interface allows you to add the following Radio Shack modules to
your system:

    1. Screen Printer (26-1151)

    2. Line Printer (26-1150)

    3. Mini-Disk System (26-1160/26-1161)

    4. Cassette Recorder number 2 (14-841)

The Screen Printer and Line Printer allow you to obtain hard copy
(printed) information generated by your TRS-80.

The TRS-80 Mini-Disk System is a small version of the floppy disk. It
provides vast storage space and much quicker access time than tape.
The number 1 disk contains about 80,000 bytes of free space for files.
Each additional disk has 89,600 bytes of file space. The Disk System
has its own set of commands that allow manipulation of files and
expanded abilities in file use. The TRS-80 Mini-Disk System uses
sequential or random access. The disks will allow use of several
additional LEVEL II commands.

    =IMPORTANT NOTE=

    Because of the presence of a Disk Controller in the Expansion
    Interface, the computer will try to input the additional
    commands.

    When the Expansion Interface is connected to the computer, it
    assumes that a Mini-Disk is connected. To use the Expansion
    Interface without a Mini-Disk, press the BREAK key on the
    TRS-80 keyboard. This will override the Mini-Disk mode and
    allow normal LEVEL II operation.


The use of two cassettes allows a much more efficient and convenient
manner of updating data stored on tape. For example, if you have
payroll data stored on tape, the information can be read, one item at
a time, from Cassette Recorder number 1, then changed or added to and
written out on Cassette Recorder number 2. The example cited is a very
simple application; however, very powerful routines can be constructed
to allow input and output of data using two tapes simultaneously.

    CAUTION

    This unit is designed to be used with Level II only. =Do not
    use with level I.=


[Illustration: FIGURE 1. Expansion Interface.*]


* Catalog Number          Description                 RAM

  26-1140          TRS-80 Expansion Interface          0K
  26-1141          TRS-80 Expansion Interface         16K
  26-1142          TRS-80 Expansion Interface         32K




SETTING UP


=Power Supplies and PCB Housing= (see Figure 2)

Remove the Power Supply Door (top right side). First connect one DC
power cord (DIN connector) to the Power connector on the PCB. Now
install the two DC Power Supplies as illustrated. Route the remaining
cords out the rear of the case. Be sure the power cords are seated in
the door cutouts before replacing the Door.

To gain access to the future expansion PCB Housing, remove the
Expansion Door from the top left side of the module.

[Illustration: FIGURE 2. Power Supplies and Future Expansion PCB
Locations.

(Illustration shows the following parts:)

POWER SUPPLY
DOOR

EXPANSION DOOR

RECESSES

RECESSES

HOUSING FOR
FUTURE
EXPANSION
BOARD

TRS-80 DC
POWER SUPPLY

REAR

EXPANSION
INTERFACE DC
POWER SUPPLY

AC POWER
CORD

DC POWER
CORD

NOTE: INSTALL EXPANSION INTERFACE DC POWER SUPPLY =FIRST=.]

    =NOTE=

    The term "port" as used in this manual refers to the openings
    into which the Cable connectors are inserted to provide an
    interconnection between the TRS-80 and the Expansion
    Interface modules.


The ports, with the exception of the Expansion Interface port, are
also covered by removable Doors. To remove these Doors, press on the
right side of the Door and it will pivot slightly. Grasp the left side
of the Door and pull out (see Figure 3 for locations).

[Illustration: FIGURE 3. Expansion Interface,
Front View--Doors Removed.

(Illustration shows the following parts:)

DOOR--MINI-DISK

DOOR--LINE
PRINTER PORT

DOOR--FUTURE
EXPANSION PORT

DOOR--SCREEN
PRINTER PORT]


=Electrical Connections= (see Figure 4)

Turn the TRS-80 so that it faces away from you. Locate the port Door
(1400083); it's at the right end of the rear panel. To remove the
Door, raise it up and slide it to the right--then lift it up and away
from the TRS-80.

Place the TRS-80 and Expansion Interface Hoods (14000217 and 14000214)
on the Ribbon Cable Connectors as shown in Figure 4. The Hoods replace
the Door on the TRS-80 and fill the opening on the Expansion
Interface. These Hoods are designed so that it is not possible to
insert the connectors upside down. They function as keyways for the
connectors. Now connect the Ribbon Cable between the left front
Expansion Interface port and the TRS-80 port.

Connect the DC Power Cord (DIN connector) to the POWER connector on
the right rear of the TRS-80 and connect both AC Power Cords to
standard 120 VAC outlets.

The interconnect cable for an expansion module is provided with that
unit. See Figure 4 for Hood Assembly and Installation.

Connect the Cassette Recorder Cable (DIN plug on one end and three
plugs on the other) to the Tape I/O connector that is located on the
rear of the Expansion Interface nearest the Power Cord exits. (Refer
to Figure 5).

Of the three plugs on the other end of the Cable:

    1. Connect the black plug to the EAR jack on the side of the
       Cassette Recorder.

    2. Connect the larger gray plug to the AUX jack.

    3. Connect the smaller gray plug to the REM jack.


    =NOTE=

    A Dummy Plug is provided with your Cassette Recorder. Plug it
    in to the MIC jack. This Plug disconnects the built-in
    microphone so it won't pick up sounds while you are loading
    tapes.

[Illustration: FIGURE 4. Front View--Interface Connections.

(Illustration shows the following parts:)

HOOD

CONNECTOR
AND CABLE

TELEPHONE-TYPE
CABLE

LINE PRINTER EDGE
CARD CONNECTOR
WITH HOOD AND
CABLE (ASSEMBLED)

LINE PRINTER PORT
(EDGE CARD)

HOOD

CONNECTOR
AND CABLE

FUTURE EXPANSION
PORT (EDGE CARD)

FUTURE EXPANSION
EDGE CARD CONNECTOR
WITH HOOD AND CABLE

SCREEN PRINTER EDGE
CARD CONNECTOR AND
CABLE (ASSEMBLED)

SCREEN PRINTER PORT
(EDGE CARD)

TRS-80 INTERFACE PORT
(EDGE CARD)

TRS-80 INTERFACE
PORT HOOD

CONNECTOR
AND CABLE

HOOD

CONNECTOR
AND CABLE

DOOR - TRS-80
EXPANSION PORT

TRS-80 PORT EDGE
CONNECTOR HOOD

CONNECTOR
AND CABLE]

Connect the Cassette Recorder Jumper Cable to the center DIN connector
on the rear of the Expansion Interface. Connect the other end to the
TAPE connector on the right rear of the TRS-80.

Connect the Video Cable from the Video Display to the VIDEO connector
on the right rear of the TRS-80.

    =NOTE=

    Your Cassette Recorders may be powered by batteries or from a
    120 VAC source. Thus, AC power cords are optional.

The TRS-80 Expansion Interface has been designed to support the Video
Display module. Set the feet of the Video Display in the recesses in
the Power Supply and PCB Housing Doors. (Refer to Figure 6).




OPERATION


    =NOTE=

    The Power switch is recessed into the front of the Expansion
    Interface to prevent accidental loss of power. Activate the
    switch with the eraser-end of a pencil or small tool of
    similar size.

Apply power to the Expansion Interface. Notice that when power is off,
the end surface of the switch is white and when power is on, it
changes to orange.




CONCLUSION


Possibly, you will not need all of the expansion modules that are
available but, we have supplied you with Hoods for cable connectors
for a complete expansion system. Use the Hoods as illustrated to
prevent accidental mismatch between the edge connectors on the PCB and
the cable connectors.

In the event that you lose a Door or Hood and want to replace it, we
have given you a Parts List. You may refer to the Parts List and
exploded diagrams to determine its Part Number. You can order
replacement parts through your local Radio Shack store.

You must have a LEVEL II BASIC TRS-80 Microcomputer to utilize the
TRS-80 Expansion Interface, the Line Printer and the Mini-Disk
modules. If you have a LEVEL I BASIC machine, it must be modified to
accept LEVEL II programs. The Screen Printer is the only expansion
module that may be connected directly to the TRS-80 Microcomputer and
that will operate with LEVEL I machines.

We are continually improving and updating our TRS-80 Microcomputer
System. You will be kept informed through our Newsletters (you are on
the mailing list), addenda and revisions to the Manual.

For the complete Electrical Connections Block Diagram, see Figure 7.

[Illustration: FIGURE 5. Rear View--Interface Connections.

(Illustration shows the following parts:)

MINI-DISK HOOD

CONNECTOR
AND CABLE

DOOR
(MINI-DISK PORT)

5-PIN AUDIO DIN
(FEMALE CONNECTORS)

5-PIN AUDIO DIN
(MALE CONNECTORS)

TO TRS-80 TAPE
CONNECTOR]

[Illustration: FIGURE 6. Placement of Expansion Interface.]

[Illustration:

                    +---------------+       +-----------+
                    | VIDEO DISPLAY |       | DC POWER  |
                    |               |       |  SUPPLY   |
                    +------+--------+       +----+------+
                           |                     |
                           |     +---------------+
                           |     |                         OPTIONAL
+---------+         +------+-----+--+       +-----------+    __
| SCREEN  |_________|               |_______|  CASSETTE |___/  |=
| PRINTER |         |    TRS-80     |       |  RECORDER |   \__|=
+---------+         +---------------+       +-----------+

TRS-80 Microcomputer System
Without Expansion Interface.]

[Illustration:

+---------+
| SCREEN  |______SCREEN PRINTER ________
| PRINTER |      INTERFACE CABLE       |
+---------+                            |
                                       |
                                       |
+---------+                            |            +----------+
| LINE    |        LINE PRINTER        |            | CASSETTE |   _
| PRINTER |-------INTERFACE CABLE--+   |       +----| RECORDER |__/ |=
+---------+         P/N 6000910    |   |       |    | (NO. 1)  |  \_|=
                                   |   |       |    +----------+ /
                                   |   |       |                /
+---------+                 +------+---+----+  |  OPTIONAL     /
|MINI-DISK|_________________|   EXPANSION   |--+  (CASSETTE___/
|(NO. 1)  |  |              |   INTERFACE   |     RECORDERS   \
+---------+ MINI-DISK    +--|   26-1140     |--+  MAY BE       \
           MULTI CABLE   |  +-+-----+-----+-+  |  OPERATED WITH \
           P/N 6000911   |    |     |     |    |  BATTERIES)     \
+---------+  |           |    |     |     |    |                  \
|MINI-DISK|  |           |    |    DC     |    |    +----------+   \
|(NO. 2)  |--+           |    |   POWER   |    |    | CASSETTE |   _
+---------+  |    FUTURE-+    |   SUPPLY  |    +----| RECORDER |__/ |=
             |  EXPANSION     |   CORD    |         | (NO. 2)  |  \_|=
             |    CABLE       |     |     |         +----------+
+---------+  |      |         |     |     |
|MINI-DISK|  |      |     INTERFACE | AUDIO DIN
|(NO. 3)  |--+      |       CABLE   |    TO
+---------+  |      |     ASSEMBLY  | AUDIO DIN
             |      |   P/N 6000907 | P/N 6000909
             |      |         |     |     |
+---------+  |      |       +-+-----+-----+-+          +---------+
|MINI-DISK|  |      |       |               |          | VIDEO   |
|(NO. 4)  |--+    FUTURE    |    TRS-80     |__VIDEO___| DISPLAY |
+---------+    APPLICATIONS |               |  CABLE   | 26-1201 |
                            +---------------+          +---------+

TRS-80 Microcomputer System with
Expansion Interface (maximum system).

FIGURE 7. Electrical Connections
Block Diagram.]




PARTS LIST


EXPANSION INTERFACE

Door, Mini-Disk                      1400212
Door, Line Printer                   1400212
Door, Screen Printer                 1400216
Door, Future Expansion Board         1400216

Hood, Mini-Disk                      1400213
Hood, Line Printer                   1400213
Hood, Screen Printer                 1400218
Hood, Future Expansion Board         1400218
Hood, TRS-80 Microcomputer System    1400214

TRS-80 MICROCOMPUTER SYSTEM

Door                                 1400083
Hood                                 1400217




LIMITED WARRANTY


    Radio Shack warrants for a period of 90 days from the date of
    delivery to customer that the computer hardware described
    herein shall be free from defects in material and workmanship
    under normal use and service. This warranty shall be void if
    the computer case or cabinet is opened or if the unit is
    altered or modified. During this period, if a defect should
    occur, the product must be returned to a Radio Shack store or
    dealer for repair. Customer's sole and exclusive remedy in
    the event of defect is expressly limited to the correction of
    the defect by adjustment, repair or replacement at Radio
    Shack's election and sole expense, except there shall be no
    obligation to replace or repair items which by their nature
    are expendable. No representations or other affirmation of
    fact, including but not limited to statements regarding
    capacity, suitability for use, or performance of the
    equipment, shall be or be deemed to be a warranty or
    representation by Radio Shack, for any purpose, nor give rise
    to any liability or obligation of Radio Shack whatsoever.

    EXCEPT AS SPECIFICALLY PROVIDED IN THIS AGREEMENT, THERE ARE
    NO OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, BUT NOT
    LIMITED TO, ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
    FITNESS FOR A PARTICULAR PURPOSE AND IN NO EVENT SHALL RADIO
    SHACK BE LIABLE FOR LOSS OF PROFITS OR BENEFITS, INDIRECT,
    SPECIAL, CONSEQUENTIAL OR OTHER SIMILAR DAMAGES ARISING OUT
    OF ANY BREACH OF THIS WARRANTY OR OTHERWISE.


RADIO SHACK [TC] A DIVISION OF TANDY CORPORATION
USA.: FORT WORTH, TEXAS 76102
CANADA: BARRIE, ONTARIO L4M 4W5

TANDY CORPORATION

AUSTRALIA
280-316 VICTORIA ROAD
RYDALMERE N S W 2116

BELGIUM
PARC INDUSTRIEL DE NANINNE
5140 NANINNE

U K
BILSTON ROAD WEDNESBURY
WEST MIDLANDS WS10 7JN

478-PERKCO-2980084     PRINTED IN U.S.A.