Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by Matt Wes » Tue, 14 Mar 2000 04:00:00



I have an Adaptec 2940 card with the following internal drives -
Philips CDD2000 CD-R, CD-ROM drive, DAT drive and a Zip drive.
The card has an external 68-pin high density (SCSI-3) connector.

I now want to connect an external Mustek 1200SP SCSI scanner.  This
scanner has a 50-pin Centronics and a 25-pin female D-connector on the
rear.

I have purchased a 68-pin SCSI-3 to 50-pin Centronics cable.  When I
plug the scanner in with this cable, the computer doesn't boot and
stops at the SCSI bus scan.  When entering the SCSI card setup
(CTRL+A) I can see the scanner on the chain (depending on the ID
address I give the scanner).  However, I can't ever get the PC to
boot.

I assume this is a termination issue, but I know very little about
this and have never used external SCSI devices before.

Is the cable the correct one ?
Do I need an external terminator on the D25F port on the scanner (if
there is such a thing) ?
What is the best combination of ID nos for all the SCSI devices (i.e.
scanner before or after the internal drives) ?
Do I need to terminate the internal drives as well as the external ?
Are there any settings or changes that I should look at in the card
setup (CTRL+A) ?

Thanks very much for any replies.  I'm a complete newbie and
desperately want to get this scanner working !
Please also mail replies to me as well as the group.

 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by SCSI Cable Gu » Tue, 14 Mar 2000 04:00:00


You are exceeding the maximum bus length most likely. Try
http://www.scsita.org/terms.html

--

http://www.cablemakers.com
SCSI Wonderland


Quote:> I have an Adaptec 2940 card with the following internal drives -
> Philips CDD2000 CD-R, CD-ROM drive, DAT drive and a Zip drive.
> The card has an external 68-pin high density (SCSI-3) connector.

> I now want to connect an external Mustek 1200SP SCSI scanner.  This
> scanner has a 50-pin Centronics and a 25-pin female D-connector on the
> rear.

> I have purchased a 68-pin SCSI-3 to 50-pin Centronics cable.  When I
> plug the scanner in with this cable, the computer doesn't boot and
> stops at the SCSI bus scan.  When entering the SCSI card setup
> (CTRL+A) I can see the scanner on the chain (depending on the ID
> address I give the scanner).  However, I can't ever get the PC to
> boot.

> I assume this is a termination issue, but I know very little about
> this and have never used external SCSI devices before.

> Is the cable the correct one ?
> Do I need an external terminator on the D25F port on the scanner (if
> there is such a thing) ?
> What is the best combination of ID nos for all the SCSI devices (i.e.
> scanner before or after the internal drives) ?
> Do I need to terminate the internal drives as well as the external ?
> Are there any settings or changes that I should look at in the card
> setup (CTRL+A) ?

> Thanks very much for any replies.  I'm a complete newbie and
> desperately want to get this scanner working !
> Please also mail replies to me as well as the group.


 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by Ed Ru » Wed, 15 Mar 2000 04:00:00


On Mon, 13 Mar 2000 23:33:09 GMT, in comp.periphs.scanners Matt West


>I have an Adaptec 2940 card with the following internal drives -
>Philips CDD2000 CD-R, CD-ROM drive, DAT drive and a Zip drive.
>The card has an external 68-pin high density (SCSI-3) connector.

>I now want to connect an external Mustek 1200SP SCSI scanner.  This
>scanner has a 50-pin Centronics and a 25-pin female D-connector on the
>rear.

>I have purchased a 68-pin SCSI-3 to 50-pin Centronics cable.  When I
>plug the scanner in with this cable, the computer doesn't boot and
>stops at the SCSI bus scan.  When entering the SCSI card setup
>(CTRL+A) I can see the scanner on the chain (depending on the ID
>address I give the scanner).  However, I can't ever get the PC to
>boot.

>I assume this is a termination issue, but I know very little about
>this and have never used external SCSI devices before.

>Is the cable the correct one ?
>Do I need an external terminator on the D25F port on the scanner (if
>there is such a thing) ?
>What is the best combination of ID nos for all the SCSI devices (i.e.
>scanner before or after the internal drives) ?
>Do I need to terminate the internal drives as well as the external ?
>Are there any settings or changes that I should look at in the card
>setup (CTRL+A) ?

IIRC, this card has two internal and one external connector, correct?
If so check the documentation, I thought you could NOT use all three
connectors simultaneously.
----

Hypersonic AirBreathing Propulsion Br.  MS 168, NASA Langley Research Center  
Hampton, VA 23681-2911              (757)864-6356(voice)   (757)864-6243(fax)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+  Please remove the * spam-buster from the front of the return address     +
+ All opinions are my own and in no way reflect NASA or anyone else        +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by J. A. M » Wed, 15 Mar 2000 04:00:00



) tweaked a mouse's tail to post:

>On Mon, 13 Mar 2000 23:33:09 GMT, in comp.periphs.scanners Matt West

>>I have an Adaptec 2940 card with the following internal drives -
>>Philips CDD2000 CD-R, CD-ROM drive, DAT drive and a Zip drive.
>>The card has an external 68-pin high density (SCSI-3) connector.

>>I now want to connect an external Mustek 1200SP SCSI scanner.  This
>>scanner has a 50-pin Centronics and a 25-pin female D-connector on the
>>rear.

>>I have purchased a 68-pin SCSI-3 to 50-pin Centronics cable.  When I
>>plug the scanner in with this cable, the computer doesn't boot and
>>stops at the SCSI bus scan.  When entering the SCSI card setup
>>(CTRL+A) I can see the scanner on the chain (depending on the ID
>>address I give the scanner).  However, I can't ever get the PC to
>>boot.

>>I assume this is a termination issue, but I know very little about
>>this and have never used external SCSI devices before.

>>Is the cable the correct one ?
>>Do I need an external terminator on the D25F port on the scanner (if
>>there is such a thing) ?
>>What is the best combination of ID nos for all the SCSI devices (i.e.
>>scanner before or after the internal drives) ?
>>Do I need to terminate the internal drives as well as the external ?
>>Are there any settings or changes that I should look at in the card
>>setup (CTRL+A) ?

>IIRC, this card has two internal and one external connector, correct?
>If so check the documentation, I thought you could NOT use all three
>connectors simultaneously.

Correct ... only TWO of the connections can be used at the same time.

Matt could ...

Daisy chain all the internals off one connector and then use the
external for the scanner.

The scanner _does_ have to be terminated.

Many 2940's (there are several 'models' of this 'card') have a high
density 50 pin connector, these can be directly connected to a 50 pin
Centronics, but if you have a 68 pin then you need a special adaptor
which will terminate the unused lines.

Many scanners work best IF you set the 2940's set-up to async and
slowest speed. See the manuals.

ID's 0 and 1 are usually reserved for internal hard drives though you
_can_ use #1. I've has best luck with keeping slower equipment on the
lower ID's (2 - 4). No rhyme or reason - just works for me. <G>

 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by Chopstick » Wed, 15 Mar 2000 04:00:00


Also check the scanner for a termination switch.  Most SCSI scanners has a
termination switch so that you can terminate the SCSI chain when your
scanner is the physically the last device on the chain (which in your case,
it is.)  If your scanner does not have a termination switch, then you will
have to buy one.  There are two types, passive and active terminators.
Passive terminators are cheaper than the active counterpart, but the active
terminators offers clearner signals on the bus.

Also, try to use an external cable that's as short as possible (I won't use
one longer than 3').

In general, the last SCSI device must be terminated.  This does not
neccessarily mean the highest SCSI  numbered device has to be terminated.

Hope that helps.


Quote:> I have an Adaptec 2940 card with the following internal drives -
> Philips CDD2000 CD-R, CD-ROM drive, DAT drive and a Zip drive.
> The card has an external 68-pin high density (SCSI-3) connector.

> I now want to connect an external Mustek 1200SP SCSI scanner.  This
> scanner has a 50-pin Centronics and a 25-pin female D-connector on the
> rear.

> I have purchased a 68-pin SCSI-3 to 50-pin Centronics cable.  When I
> plug the scanner in with this cable, the computer doesn't boot and
> stops at the SCSI bus scan.  When entering the SCSI card setup
> (CTRL+A) I can see the scanner on the chain (depending on the ID
> address I give the scanner).  However, I can't ever get the PC to
> boot.

> I assume this is a termination issue, but I know very little about
> this and have never used external SCSI devices before.

> Is the cable the correct one ?
> Do I need an external terminator on the D25F port on the scanner (if
> there is such a thing) ?
> What is the best combination of ID nos for all the SCSI devices (i.e.
> scanner before or after the internal drives) ?
> Do I need to terminate the internal drives as well as the external ?
> Are there any settings or changes that I should look at in the card
> setup (CTRL+A) ?

> Thanks very much for any replies.  I'm a complete newbie and
> desperately want to get this scanner working !
> Please also mail replies to me as well as the group.

 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by David Chie » Wed, 15 Mar 2000 04:00:00


Quote:> address I give the scanner).  However, I can't ever get the PC to
> boot.

Besides the other comments:
Set max speed to 10MB/s (maybe 5 for some scanners).  Try the various
disconnect/sync settings.

And hope it isn't my wierd Epson 1200S bug -- didn't work at all with
my 2930U2 (stopped booting when it hit the miniport *.mpd driver unless
I momentarilly turned the scanner on, then off again) but did with a
2906 card that came with the scanner.  Had to wipe W95 and reinstall
everything to get everything to work w/o a hitch -- ie. same setup as
before I wiped the HD, but whatever little thing was different made
the difference.

 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by George Li » Wed, 15 Mar 2000 04:00:00


Sound like you have the right hardware.
If I understand you correctly, you are using the internal 50pin and external
68pin.
You need to disable termination on the scsi card and terminate the scanner.
In your case it doesn't sound like you have any wide scsi devices so
high-termination is a moot issue.  Normally, you're 68-50 pin converter
needs the high bits to be properly terminated. (usually not the case with
cheap converters).
Remember the devices (phyically) at each end of the bus need to be
terminated.

Also, make sure the scanner cable is not too long.  Try to keep it 3 ft or
less.

(A physical description of SCSI IDs and physical locations would be useful)

George



> On Mon, 13 Mar 2000 23:33:09 GMT, in comp.periphs.scanners Matt West

> >I have an Adaptec 2940 card with the following internal drives -
> >Philips CDD2000 CD-R, CD-ROM drive, DAT drive and a Zip drive.
> >The card has an external 68-pin high density (SCSI-3) connector.

> >I now want to connect an external Mustek 1200SP SCSI scanner.  This
> >scanner has a 50-pin Centronics and a 25-pin female D-connector on the
> >rear.

> >I have purchased a 68-pin SCSI-3 to 50-pin Centronics cable.  When I
> >plug the scanner in with this cable, the computer doesn't boot and
> >stops at the SCSI bus scan.  When entering the SCSI card setup
> >(CTRL+A) I can see the scanner on the chain (depending on the ID
> >address I give the scanner).  However, I can't ever get the PC to
> >boot.

> >I assume this is a termination issue, but I know very little about
> >this and have never used external SCSI devices before.

> >Is the cable the correct one ?
> >Do I need an external terminator on the D25F port on the scanner (if
> >there is such a thing) ?
> >What is the best combination of ID nos for all the SCSI devices (i.e.
> >scanner before or after the internal drives) ?
> >Do I need to terminate the internal drives as well as the external ?
> >Are there any settings or changes that I should look at in the card
> >setup (CTRL+A) ?

> IIRC, this card has two internal and one external connector, correct?
> If so check the documentation, I thought you could NOT use all three
> connectors simultaneously.
> ----

> Hypersonic AirBreathing Propulsion Br.  MS 168, NASA Langley Research
Center
> Hampton, VA 23681-2911              (757)864-6356(voice)
(757)864-6243(fax)
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> +  Please remove the * spam-buster from the front of the return address
+
> + All opinions are my own and in no way reflect NASA or anyone else
+
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by Randy Burnet » Wed, 15 Mar 2000 04:00:00


Matt,

You need to terminate the scanner, non-terminate the 2940 card, and
terminate the last internal device on the chain. Keep in mind that, unless
you've got the 2940U2W card, you can't use both internal card connectors
along with the external connector. The external cable should be fine. One
more interesting note about SCSI: devices get serviced in reverse priority
(ID7, 6, 5, 4, 3, 2, 1, 0). I would put the slowest SCSI devices on the
lower IDs. Hope this helps.

Randy


Quote:> I have an Adaptec 2940 card with the following internal drives -
> Philips CDD2000 CD-R, CD-ROM drive, DAT drive and a Zip drive.
> The card has an external 68-pin high density (SCSI-3) connector.

> I now want to connect an external Mustek 1200SP SCSI scanner.  This
> scanner has a 50-pin Centronics and a 25-pin female D-connector on the
> rear.

> I have purchased a 68-pin SCSI-3 to 50-pin Centronics cable.  When I
> plug the scanner in with this cable, the computer doesn't boot and
> stops at the SCSI bus scan.  When entering the SCSI card setup
> (CTRL+A) I can see the scanner on the chain (depending on the ID
> address I give the scanner).  However, I can't ever get the PC to
> boot.

> I assume this is a termination issue, but I know very little about
> this and have never used external SCSI devices before.

> Is the cable the correct one ?
> Do I need an external terminator on the D25F port on the scanner (if
> there is such a thing) ?
> What is the best combination of ID nos for all the SCSI devices (i.e.
> scanner before or after the internal drives) ?
> Do I need to terminate the internal drives as well as the external ?
> Are there any settings or changes that I should look at in the card
> setup (CTRL+A) ?

> Thanks very much for any replies.  I'm a complete newbie and
> desperately want to get this scanner working !
> Please also mail replies to me as well as the group.

 
 
 

Beginners help required - connecting external SCSI to AHA-2940 with internal drives

Post by Matt Wes » Fri, 17 Mar 2000 04:00:00


Thanks for everyone's replies.

The existing SCSI IDs are : CDD2000 CD-R on ID2, Teac CD-ROM on ID3,
DAT drive on ID4, Zip drive on ID5 and AHA-2940AU on ID7.  This is one
50-pin internal chain.
Externally is the scanner (is ID 1 recommended ?) on a short 68-pin to
a Centronics 50-pin (scanner end).  There is no SCSI termination
switch on the scanner.  There is a spare D25F SCSI port.

My questions :

What ID should I set the scanner to ?

Should I lower the speed for that ID ?  All ID's are set to 20mb/s
(max) in the card setup.

In the SCSI card setup, the setting "Host adapter SCSI termination"
exists with auto, enable or disable as the choices.  What should I set
this to (currently 'auto') ?

How do I terminate the scanner ?  I've been looking in the Inmac
catalogue at the available terminators.  There are passive, active or
differential.  Which do I need ?

Do I use a D25M terminator in the other spare port on the scanner ?
Do I use a Centronics 50 (M/F) terminator ?  I assume this one fits
between the scanner port and my cable.

Thanks for any help.

 
 
 

1. Can a UMAX SCSI scanner with D25 connector be connected to an Adaptec AHA-2940 Ultra

Situation as follows:

- Windows 2000 or XP
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- SCSI board Adaptec 2040

The scanner expects an cable with D25 connector
The card has to outputs:
    internal: 50 pin flat cable
    external: female 50 pin High density connector

Is there any way to connect the scanner? I am not a SCSI guru and not sure
if with all these combinations SCSI 1/2/3, active vs passive terminator, and
single ended vs. differential  the whole thing could work in theory at
least.

If it COULD work, I will be helpfull by any hint of how to connect them:
    1. by byuing an ?? to D25 cable (couldnt find anything here) or
    2. by building my own from the 50 pin flat cable. I would need PINOUT.

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