SUMMARY UPDATE: SCSI jumper settings and ID selectors

From: Conner McCleod (
Date: Fri Dec 17 1999 - 12:45:21 CST


I have added the configuration for connecting an external SCSI (Wide = 15
targets) case to a Wide Internal disk. The jumper configuration for Bit 8,
Bit 4, Bit 2, and Bit 1 are as follows:

8 4 2 1 BITS:
: : : : SCSI ID 0
: : : [:] SCSI ID 1
: : [:] : SCSI ID 2
: : [:][:] SCSI ID 3
: [:] : : SCSI ID 4
: [:] : [:] SCSI ID 5
: [:][:] : SCSI ID 6
: [:][:][:] SCSI ID 7
[:] : : : SCSI ID 8
[:] : : [:] SCSI ID 9
[:] : [:] : SCSI ID 10
[:] : [:][:] SCSI ID 11
[:][:] : : SCSI ID 12
[:][:] : [:] SCSI ID 13
[:][:][:] : SCSI ID 14
[:][:][:][:] SCSI ID 15

The following connections were tested using an HP St34573W disk. Using the
above Bit configuration, the cable connections are as follows. On the
actual SCSI target selector from TOP to BOTTOM the five cables are Red,
White, Yellow, Green and Black. The Black appears to always be
Neutral/Ground. Let me clarify. On the SCSI selector the five cables are
soldered from top to bottom as mentioned above. I am referring to internal
part of the SCSI selector, not the external part where you get the + and -
choices to change your targets.

On the actual jumpers on the Disk or CDROM, the bit configuration is as
Bit 8 has pins labeled low=1, high=2;
Bit 4 has pins labeled low=3, high=4;
Bit 2 has pins labeled low=5, high=6;
Bit 1 has pins labeled low=7, high=8.

Red is then connected to pin 2, White is connected to pin 4, Yellow is
connected to pin 6 and Green is connected to pin 8. The bottom pins are all
touched by black (normally, using one big jumper that touches pins 1, 3, 5,
and 7.) In effect the connections are:

Bit8 has pins labeled, high = pin2 = connects to Red
Bit4 has pins labeled, high = pin4 = connects to White
Bit2 has pins labeled, high = pin6 = connects to Yellow
Bit1 has pins labeled, high = pin 8 = connects to Green

Bit8, 4 , 2 , & 1 have the lower pins as: low=1, low=3, low=5, low=7
connected to the one cable. Again the are all connected using one
horizontal black jumper that covers all the bottom pins. In the case of
this HP drive the black is actually touching pin 5, but the jumper covers
pins 1, 3, 5, and 7.

I believe that we have covered the majority of SCSI targets for SCSI I
(Centronics), II (50 pins) and Wide (68 pins) devices, including how to
attach them to a SCSI selector and an external case.

Conner McCleod


The original credits and SUMMARIES are attached at the bottom.

The procedure for configuring SCSI targets is basically to use the jumpers
as describe and to check them against a SUN workstation using "probe-scsi"
at the EPROM. You can also use the "scan" option on HP-UX workstations.
You can accomplish the same by seeing the target configuration on a PC
using an ADAPTEC 2940 W/UW as the system boots up or by pressing Alt-F2 to
go into the SCSI configuration option.

If you can not get the documentation online, and if you cannot solve the
SCSI ID problems with this email, then trial and error as described above
should help you to configure the SCSI targets. Last, if you can't get the
SCSI ID selector to work, then just set the device's jumpers make a note of
the target and glue the darn selector into place!

Thanks to all the people who sent their answers.

Final Jumpered configuration for the HP C3044U drive using an external SCSI
ID selector was:

‡::‡:::: ‡: :421

>From Left to Right jumpers 1, 4, and 9 needed to be in place for the drive
to use an external SCSI ID selector, without it it would not recognize the
external selector. The pins labeled 421 and Bit 4, Bit 2 and Bit 1. The
were wired to the External Device as follows:

. . . "Yellow, Blue and Red from Left to Right."
. "Black only from Left to Right - with the other two right-most
pins unused."

Configuring jumper settings for SCSI devices. Some of these devices you
have the bit 4, bit 2, and bit 1 jumpers that give you the desired SCSI ID

These three are the SCSI ID jumpers
(Bit 4, Bit 2, Bit 1)

: : : SCSI ID 0
::[:] SCSI ID 1
:[:]: SCSI ID 2
:[:][:] SCSI ID 3
[:]:: SCSI ID 4
[:]:[:] SCSI ID 5
[:][:]: SCSI ID 6
[:][:][:] SCSI ID 7 "The actual SCSI controller"

Once you have the actual jumpers for a BARRACUDA ST5150WC/DC SCSI drive:

: : : : SCSI ID 0
: : : [:] SCSI ID 1
: : [:] : SCSI ID 2
: : [:][:] SCSI ID 3
: [:] : : SCSI ID 4
: [:] : [:] SCSI ID 5
: [:][:] : SCSI ID 6
: [:][:][:] SCSI ID 7
[:] : : : SCSI ID 8
[:] : : [:] SCSI ID 9
[:] : [:] : SCSI ID 10
[:] : [:][:] SCSI ID 11
[:][:] : : SCSI ID 12
[:][:] : [:] SCSI ID 13
[:][:][:] : SCSI ID 14
[:][:][:][:] SCSI ID 15

Ok, here is the thing when you want to use a generic CENTRONICS SCSI case
(SCSI 1) on one of these drives you can kind of figure out what the pattern
is… for example for a drive in question the "C3044U disk and its jumper
settings" the jumpers are configured as detailed above. However, how do
you connect these to the generic SCSI selector cables (third party vendor
stuff). I found a patter for the SCSI 1 and SCSI 2, but not for the Wide
devices "the ones with the 15 SCSI IDs" The generic SCSI cases come with
four cables… Red, Blue, Red and Black. I figure out how to attach these
devices to the SCSI selectors on the C3044U drive and also on one of those
old SUN 150MB tape drives.

Here are the SCSI jumpers for the HP C3044U drive:

: : : "bit 4, bit 2, and bit 1"

The thing is that the four cables connect not Vertically on the jumpers like
one would expect, but rather they bisect the jumpers Horizontally. Three of
the cables go on the TOP pins and one goes on the bottom. Here are the
cable pins for the generic SCSI ID selector:

The dots represent three jumpers displayed in two lines : : :

. . . "Yellow, Blue and Red from Left to Right."
. "Black only from Left to Right - with the other two right-most
pins unused."

Here are the jumper pins configurations for an old SCSI SUN 150 MB TAPE,
those old heavy ones with the metal casing:

. . . "Yellow, Blue and Red from Left to Right."
        . "Black, with the two left pins unused."

For the SUN drive the actual position of the black cable/pin is reversed,
but the pattern seems to be the same.

I followed my four cable pattern to an NEC 2X SCSI CD-ROM READER MODEL
CDR-510. I was able to get the CDROM to work with the same four cables and
a generic SCSI ID selector.

. . . "Yellow, Blue and Red from Left to Right."
. "Black only from Left to Right - with the other two right-most
pins unused."

The pins in SCSI devices appear to change drastically enough that you need
to look up the documentation some where, on the net, the original documents
or by asking. One thing that I do recommend is that if anyone has one of
those SCSI selector ribbons, the kind that comes with the original SCSI ID
selector or the original box. You can study the actual electrical wires
inside the ribbon to determine the SCSI ID selector connections.

As a general rule I was not able to determine what the four cables are for.
It might be that the top cables are all positives and the bottom cable is
either a negative or a ground. It would be nice if someone new the actual
basis of the SCSI ID cable configuration for SCSI 1,2 and SCSI W/UW devices.
  Since most generic SCSI cases are only CENTRONICS (SCSI 1) I was not able
to workout the pin/cable connections for a SCSI device with the 15 SCSI ID
targets like W/UW SCSI. However, I did manage to recycle five older SCSI

I have two other projects that I am working on… SCSI ID projects. The first
is an HP DDS2 4MM DRIVE MODEL C1504B. This one should be interesting since
its got the pins Bit 4, Bit 2, and Bit 1 in this order:
.. .. .. .. .

The first two (left) are TERMINATION, the second six are labeled SCSI 2,
SCSI 1, and SCSI 0. Pin 9 is missing and pin ten is labeled NC. This one
should be easy since it is fairly new and documentation is available on the
net. There are also eight little dip switches on the bottom of the device.
I believe that the pins labeled SCSI 2, SCSI 1, and SCSI 0 are bits 4, 2,
and 1 respectively. Note that the jumpers are horizontally arranged on
this device.

My last little SCSI project, after which, I'll probably never touch again
JUMPERS, is that of a Storage Dimensions Multi-pack. On the back are the
old fashioned SCSI ID selector wheels with targets 0-7; the four available
SCSI ID selectors are labeled DR1 ID, DR2 ID, DR3 ID, and DR4 ID. On the
inside of the Multi-pack are the matching pins for the SCSI ID selector
wheels. They are 15 pins per DRx ID and they are labeled SW1/J1 and SW2/J2.
  Here is the pin layout for the wheels:


They are actually vertical, but were drawn horizontally to save space. I'll
probably have a harder time finding out what the pin configurations are for
these devices.

Ok…. That is it for SCSI ID targets and SCSI ID controllers.

Conner McCleod


C3044U disk and jumper settings

Thanks to:
Kevin Davisson <>
"ajitkumar rane" <> (Eddie AFC Evans)

The solution was to configure the last three jumpers
as described below. However, that in it self did not
work. I was about to throw the disk out the window...
when I removed the midle three jumpers and it worked!
It seems that those jumpers are telling the drive to
use the Ribon for the SCSI selector. Removing them
allow me to configure the last three jumpers as
described by Kevin Below. Thanks Admins.

Conner McCleod

Jumper description
:=Un-used jumper pins
?=Used jumper pins
‡=Used by Ribbon
Blank=No jumper or jumper pins.

?::::::: ?: :‡:‡

Currently this is the layout of the jumper pins
:::::::: :: ::::

There are actual jumpers on the drive by default
?::::??? ?: ::::

The ribbon normally connects to
::‡‡:::: :: :???

Kevin Got the SCSI (2^3) configurations right on the

Not sure what these are for, possibly terminator power
and/or auto spin
at power on.
?:??:??? ?: :???
               These three are the SCSI ID jumpers
(Bit 4, Bit 2, Bit 1)

::[:] SCSI ID 1
:[:]: SCSI ID 2
:[:][:] SCSI ID 3
[:]:: SCSI ID 4
[:]:[:] SCSI ID 5
[:][:]: SCSI ID 6

(of course scsi 7 is the ID of the card and can't be
used for a

Ajit was also in the right direction:

I have not come across such model but generally the
SCSI ID jumpers are

situated on the right hand side near the DC power
connector of the drive. in you diagram the right hand
side 3 jumpers (on 3 of which ribbon is connected)
should probably be the scsi id's.

?:‡‡:??? ?: :421

124 - scsi id's.


Evans was on the right path also:

I think that here
the right most three _'s
will be your addy.
421 is the layout.
But I could be wrong.
I was wrong before.
It was a Thursday.

Term, sync, spindle delay, are *probably* the jumpered
ones. Do you have the harness? (In another machine?)
I did a bit of this a year or two ago....

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