Very basic SCSI questions

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precertvideo
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Very basic SCSI questions

Post by precertvideo » Sun Mar 02, 2014 6:28 pm

Hello,

I am attempting to connect to some of my cameras with SCSI for some reason. I am also a partial dunderhead so I need this sort of thing explained very simply :D

I'm trying to get from a Windows 95 or XP laptop via PCMCIA or parallel ports with adapters to Kodak DCS 200/4xx.

Connection begins with either Centronics type low density 50 pin or High Density 50 pin SCSI-2 connectors.

Camera has DB25 socket as I'm sure you know.

1. How do I tell if I have a printer cable or a SCSI cable? If there is any difference.

2. Is it possible to use a gender changer in between 2 cables, eg. this chain

Laptop > Centronics 50 > Gender change > Centronics 50 > DB25 > Kodak DCS

Many thanks in advance, JR
DCS serial no. survey
RC-760, EOS-1D & Ds Mk I, II, III, EOS*DCS-3, 5, DCS, DCS-200ci, 420, 460, D1, D1H & X, D2H & X, E2, F, F2, F3, F4, MVC-2000, 5000, 7000, RD-175, 3000, EF 50mm f/1.0, Audi S2, Porsche 911, GSX-R1000 K9

Stan Disbrow
Posts:579
Joined:Fri May 20, 2005 7:33 pm
Location:Raleigh, NC USA

Re: Very basic SCSI questions

Post by Stan Disbrow » Mon Mar 03, 2014 12:43 am

Hi,

You are opening a can, no, a barrel of worms here. But, I will try and help. Prepare to take a drink from a fire hose....

No way to run SCSI from parallel or serial ports. They are their own adapters. There used to be PCMCIA SCSI cards, but may no longer be available.

SCSI is 50 pins for SCSI 1. 68 pins for SCSI 2.

The SCSI 1 50 pin connector is a Centronics style, but larger than the Printer which is 36 pins. You know because they do not mate up.

SCSI is differentially driven, so 25 pairs of twisted conductors. Apple had to do it wrongly, and used a 25 pin D shell connector swiped from the old serial port standard. They wired common mode since they were missing half the wires. So, the cable distance for Apple SCSI is one third that of the rest of the world.

Kodak used the Apple style of SCSI because to deal with their files required a Twain driver, and that meant Photoshop, which was originally an Apple Mac program.

That brings up another whole mess. You need to run an ancient Photoshop to use the Twain drivers. The old PS will not run right on a new machine, so you need an old one of those, too. With an old OS to boot.

I last ran this sort of lashup on a 460 using a first or second gen Apple Power PC Mac. I think I also did on a P3m laptop with Win 2k and a PCMCIA SCSI card. I think you could run XP, and as late as a P4m and XP with PS 6.

There are 50 pin to 25 pin SCSI adapters.

You also need to understand SCSI termination, something that foiled every SCSI user in the world, except for me. SCSI is a daisy chain scheme. It needs termination at *each end*. SCSI stuff comes *unterminated*. You have to turn it on whatever the end device on each end of the chain is. Or it works really wierd. And you will pull your hair out in frustration.

A PCMCIA SCSI card, fortunately, is terminated. A desktop card is not. They expect a desktop card to be in the middle, with internal hard drives to be connected, with a terminator on the last drive in the case. If you have no internal SCSI drives, you are going to have issues. It is unlikely that an internal SCSI card found surplus will have a terminator on the ribbon cable port.

The Kodak cameras are terminated only for one address. The others are unterminated. I always used an external terminator block, looks like a dongle, between the cable and the camera. This is because Apple had the controller at ID 0 but IBM had it at ID 6 and Kodak put the internal terminated ID at 6 and that would never work with a controller at 6.

None of all that is going to make *any* sense to you. ;)

Stan
Amateur Photographer
Professional Electronics Development Engineer

precertvideo
Posts:97
Joined:Fri Nov 03, 2006 10:34 am
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Location:England

Re: Very basic SCSI questions

Post by precertvideo » Mon Mar 03, 2014 8:11 am

Thank you Mr. Disbrow, you deserve an award for most knowledgeable.
No way to run SCSI from parallel or serial ports.
I mean I have a Belkin parallel to SCSI adapter. And I have 2 different PCMCIA to SCSI cards.

I thought the 50 pin might also be for printers, so that's easy.

I have Photoshop 5 with TWAIN drivers, which I have successfully used with files already on the computer.

Amazingly I do understand the termination-Set camera to "PC" for active termination. Not going to use a desktop.

What do reckon to the gender changer? Work or not work in your opinion?

Sincere thanks for all your help,

Jonathan
DCS serial no. survey
RC-760, EOS-1D & Ds Mk I, II, III, EOS*DCS-3, 5, DCS, DCS-200ci, 420, 460, D1, D1H & X, D2H & X, E2, F, F2, F3, F4, MVC-2000, 5000, 7000, RD-175, 3000, EF 50mm f/1.0, Audi S2, Porsche 911, GSX-R1000 K9

Stan Disbrow
Posts:579
Joined:Fri May 20, 2005 7:33 pm
Location:Raleigh, NC USA

Re: Very basic SCSI questions

Post by Stan Disbrow » Mon Mar 03, 2014 11:55 am

Hi,

I never heard of a parallel to SCSI adapter. The parallel port is a lot slower than SCSI, but I can see where someone could send data thru a parallel printer port to a SCSI controller imbedded in the adapter if one accepted the slower speed. The PCMCIA card would be faster, of course. Not that speed is all that important with the camera.

So, all you need to make it work is an adapter from the 50 pin differential SCSI to the 25 pin Apple. Those were common once upon a time, so they are out there. Both as block adapters and short cables. :)

Stan
Amateur Photographer
Professional Electronics Development Engineer

precertvideo
Posts:97
Joined:Fri Nov 03, 2006 10:34 am
antispam:No
Location:England

Re: Very basic SCSI questions

Post by precertvideo » Wed Mar 05, 2014 9:05 pm

Have ordered an adapter, will let you know if it works/the next problem!

Thanks for all your help. Jonathan
DCS serial no. survey
RC-760, EOS-1D & Ds Mk I, II, III, EOS*DCS-3, 5, DCS, DCS-200ci, 420, 460, D1, D1H & X, D2H & X, E2, F, F2, F3, F4, MVC-2000, 5000, 7000, RD-175, 3000, EF 50mm f/1.0, Audi S2, Porsche 911, GSX-R1000 K9

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