CDR-1501  (250-1091)          Jumper Settings          Faxback Doc. # 5280

Note: This CD-ROM drive does not meet MPC specification.

Note: Do not attach this drive to the (25-1097) Soundblaster Pro Board.

The drive-select jumpers on the back panel of the drive are used to
designate the drive number for the drive connected to the adapter (ribbon)
cable. Normally, you do not need to change the settings; you use the other
settings when you install more than one CD-ROM drive in your computer.

    ┌───────────────────┐
    │┌─┐         ┌─┐┌─┐ └┐
    ││o│ o  o  o │o││o│  │
    ││o│ o  o  o │o││o│  │
    │└─┘         └─┘└─┘  │
    └─┬──┬──┬──┬──┬──┬───┘
      │  │  │  │  │  └──Terminator
      0  1  2  3  │
                  └─────DRQ/Wait

This CDR 1501 drive is capable of being daisy chained with up to three more
CDR-1501 drives.  Radio Shack does not sell a cable to support this
configuration.  The customer will have to find a 40 pin cable locally.

Preparing the Adapter Interface:

The adapter interface allows the CD-ROM drive and your computer to
communicate with each other. Before you install the adapter interface, you
must select its address and the DMA channel settings.

Note: The IRQ channel setting does not affect the CD-ROM drive's operation.

Setting the Address:

The adapter interface's address tells the computer where to look for the
CD-ROM drive. In most cases, the factory-set address (340H) works. However,
if there is another device in your computer that uses that address, such as
a 3COM or LAN board, you must change the CD-ROM drive's address to prevent
a conflict.

If you set and address other than the default, you must manually edit your
computer's config.sys file (as described in "Manually Editing Config.sys")
to enter the new address after you perform software setup.

Refer to the following chart to set the adapter interface address to one of
the ten address settings using the jumper block labeled SW1.

To select an address other than the factory setting, move the jumper to the
appropriate position.

300H           310H           320H           330H           340H*
(No Jumper)
o o o o o o    o o x o o o    o o o x o o    o o x x o o    o o o o x o
o o o o o o    o o x o o o    o o o x o o    o o x x o o    o o o o x o

350H           360H           370H           380H           390H

o o x o x o    o o o x x o    o o x x x o    o o o o o x    o o x o o x
o o x o x o    o o o x x o    o o x x x o    o o o o o x    o o x o o x

* Factory setting

Note: Some address settings require more than one jumper. Additional jumpers
are available at your local Radio Shack store.

Setting the DMA Channel:

Your computer uses two methods for reading data from the CD-ROM drive:
Direct Memory Access (DMA) transfer and software transfer. If your computer
is a Tandy 1000 or other PC/XT compatible computer, DMA transfer is faster.

Jumper block SW3 sets the DMA channel. The adapter interface is preset for
software transfer (no jumpers are installed). If you want to use DMA
transfer, you must select the DMA channel by installing the jumpers in pairs.
For example, to select DMA Channel 1, install a pair of jumpers on the DRQ1
and DACK1 posts.

Normally you can use DMA Channel 3 for the CD-ROM drive. However if your
computer is Tandy 1000 or other PC/XT compatible computer, DMA Channel 3 is
used for the hard disk drive, so set the DMA channel to 1. Channel 2 is
normally used for floppy disk drive and should not be used.

If you select DMA transfer, you must manually edit your computer's
config.sys file after you perform software setup.

Notes:

* If your computer is using all available DMA channels, you must use
  software transfer. If you are not sure whether your computer is using all
  available DMA channels, contact your local Radio Shack store.
* If you are using software transfer, you should not select a DMA channel.

SW3   o o o o o o   (No Jumper Default)
      o o o o o o
      D D D D D D
      R A R A R A
      Q C Q C Q C
      1 K 2 K 3 K
        1   2   3

Adapter Interface Board Layout:

     ┌───────────────────────────────────────────────┬───────┐
     │                                  ┌───────┐    │ ┌─────┘
     │                  ┌──────────┐    │       │    │ │
     │┌─┬─┬─┬─┬─┬─┐──┐  │          │    │       │    │ │
     ││o│o│o│o│o│o│  │  └──────────┘    │       │    │ │
     ││o│o│o│o│o│o│  ├Base Address      └───────┘  ┌─┤ │
     │└┬┴┬┴┬┴┬┴┬┴┬┘──┘Jumpers     ┌─────┐          │ │ └─┐
     │ 0 1 2 3 4 5                │     │       ┌──┘ │ ┌─┘
     │                            │     │       │    │ └─┐
     │ ┌───────────────────────┐  │     │       │    │ ┌─┘
     │ │                       │  │     │       │    │ │
     │ │                       │  │     │       └──┐ │ │
     │ └───────────────────────┘  │     │          │ │ │
     │    ┌─┬─┬─┬─┐──┐            │     │          └─┤ │
     │    │o│o│o│o│  ├IRQ         │     │            │ │
     │    │o│o│o│o│  │Settings    └─────┘            │ │
     │    └─┴─┴─┴─┘──┘(Not Used)                     │ │
     │  ┌─┬─┬─┬─┬─┬─┐──┐                             │ │
     │  │o│o│o│o│o│o│  ├DMA Channel                  │ │
     │  │o│o│o│o│o│o│  │Jumpers                      │ │
     │  └┬┴┬┴┬┴┬┴┬┴┬┘──┘                          ┌──┤ │
     └───┼─┼─┼─┼─┼─┼──────────────────────────────┘  └┐│
         │ │ │ │ │ └DACK3                             ││
         │ │ │ │ └DRQ3                                └┘
         │ │ │ └DACK2
         │ │ └DRQ2
         │ └DACK1
         └DRQ1

(dtc-08/02/93)