Well, I must learn to stop trusting my memory.

I have a reeeeally old HP SCSI scanner. It came to me with an equally old ISA SCSI card. When I upgraded my computer, I had to get rid of it because I had no ISA slots.

The scanner was not with me this summer, and I thought it was 50 pin which would have worked out because I have a SCSI card with an external 50 pin connector. So I would just have to daisy-chain the scanner and my tape backup.

But the scanner is not 50 pin. A count of the pins reveals 25. I don't know much about SCSI, but I haven't heard of 25 pin SCSI components.

Do they still make SCSI cards for my device? Will I have conflicts with my devices?

Most (Edit: Okay, many) SCSI scanners were 25-pin. Don't ask me, but Macs also had 25-pin SCSI connectors. Regardless, you can go buy a cable that'll work just fine. You might have termination issues, though. Do you have other external SCSI devices? If not, then you should be okay. If you do, I'd suggest seeing if you can find a 50-to-25 pin adapter (I don't know that these exist (Edit: I just checked, and they do, although they're pretty pricy)) and placing the scanner not at the end.

Sounds like you have an HP. I have a Scanjet IIcx that came with that crappy-ass ISA card. Everytime I had to reinstall Windows, getting that thing to work was a pain.

Currently, I have a generic PCI SCSI card for the purpose of keeping that workhorse of a scanner. My freind Moe always has weird cables. This is likely the one you need. It's the one I have. Works like a charm.

Rats, beaten out by Rob. This site is good, it's solved a few tough scsi connection problems for me in the past.

http://www.ramelectronics.net/html/scsi_adapters.html

-Zeke

Thanks! That's perfect. So you guys would suggest that if I have the scanner (yes, it's an HP ScanJet 4c) and a tape backup, that the tape backup go on the end of the chain? I assume I'd need two of those cables then, with different genders, so that I can connect the tape drive to the scanner, right? Or do you think it's safe to just put the scanner on the end?

There are many cables on that site. It would be a good idea to draw what you want to do so you can see what you need. Simply because I know what comes with a SCSI HP scanner, I would say put that on the end of the chain with the provided terminator. So... you would go:

SCSI card ----> Tape Backup ----> Scanner ----> Terminator

Well, that's how I would do it at least.

The problem with that scenario is that I have no idea how DB25 SCSI works, and I'm not convinced that everything will get terminated correctly.

Boy, I'm not sure there is a good solution here. In a perfect world, I'd have a cable that had three 50-pin connectors on it, hook the scanner up in the middle with an adapter and terminate after the tape drive. But I'm not aware of an external cable that has more than two connectors. I might look at something like the external->internal->external cable like the one that's likely inside your tape drive's case.

This might all be overkill anyway, and it'll work because DB25 will somehow terminate all 50 pins properly. But I just don't know.

IIRC, 25 pin and 50 pin SCSI is identical except at the termination side. half of a fifty pin connector is used for grounding anyway. if you like i can (laboriously) give you the pin outs for most kinds of connectors and terminators, but only if you REALLY need it.
If you have a 25 pin connector on your card and the scanner, it'll work. If you have a 25 pin on the card and a 50 pin centronics on the scanner it'll work. If you have a 68 pin on the card and 25 pins on the scanner it'll work. most modern cards are auto-sensing for this and change the pin outs and speed appropriately.
Having said that, it is a rare form of voodoo to get all the combinations working correctly. As long as you have similar types and turn on the peripherals (scanners etc) before booting the computer you're cool.

Being a bus, terminators must be at each end. Usually the card has termination by default. The exception is where there is an internal connector and the card is in the middle of the chain. If your scanner has an internal terminator, it must be at the end. make sure that the IDs are all different and you should be fine.

Would I be correct in assuming that if I simply bought a new 25 pin SCSI card, that would simplify the entire process? Because I will if I need to

Would I be correct in assuming that if I simply bought a new 25 pin SCSI card, that would simplify the entire process?

Robricc and muzza are right: the process is already simple.

You've got no internal devices on the SCSI bus, right? Just the card, the tapestreamer, and the scanner, right? In that case it's as robricc drew it:

SCSI card (terminated; modern cards self-terminate automatically)
|
| SCSI cable
|
Tapestreamer (not terminated)
|
| SCSI cable
|
Scanner (terminated)

If the scanner doesn't have a DIP switch to enable termination, you'll need a separate physical terminator on the scanner's other SCSI connector (it has two, right?)

The two SCSI cables in the picture can be either 50-to-25 or 50-to-50 as necessary. 25-pin SCSI is just a different pinout for exactly the same thing as 50-pin SCSI. You also have to make sure that the card, tapestreamer, and scanner are all set to different SCSI IDs (the card is traditionally 7 but you can choose any two of 0-6 for the other things; they don't have to be daisychained in ID order).

Peter

Yes, that will probably be the cheapest option too. Assuming you can find such a card with PCI interface. I've looked on the sites of Adaptec and Tekram, only to find that even their simplest SCSI cards' external adapter is 50 pin.

25-pin SCSI is just a different pinout for exactly the same thing as 50-pin SCSI.

That's a piece of information I was missing, and, if true, means that Dignan can put them in whatever order he desires (probably putting whichever device for which he has an appropriately pinned terminator at the end).

Sorry to insert any confusion.

I only have a terminator for the tape drive. That's the metallic cap on he connector, right?

Man, this area sucks for computer stores. the only places I can buy hardware is staples and a Best Buy 20 minutes away. Nothing else. Of course, neither carries SCSI cards. I'm going to check, but I doubt either sells the appropriate cables either. Damn.

A terminator is a device that prevents reflections off the end of the bus. They usually look like a connector with no cable attached to it. They definitely attach to the pins on the device. Basically, each SCSI device will have two SCSI connectors, so that the bus can pass through it. The last device needs to have a terminator on the connector that would otherwise be unused.

Take a look at these terminators to get an idea of what they look like.

Wow, I feel dumb now. I just got around to taking a second look at all of the connectors. What I hadn't seen earlier is that the scanner had a second input. So when I had the old 25 pin SCSI card in there, it was connected by a cable that went from the 25 pin card to the 50 pin connector on the scanner. But the second input on the scanner is 25 pin! So basically, I simply turned the cable around, 25 pin into the scanner and 50 pin into the tape drive, and I'm up and scanning after a reboot!!!

Just goes to show, kids. Look for the simple solutions first.

Oh, and a special thanks to tanstaafl for sending me the HP Deskscan II software. I now I finally have more control over my scans than just "Preview" and "Final"

What a happy ending. I'm just gonna (snif) cry.

My college just threw out a CD tower of seven 6x speed scsi drives. getting it going would have been one thing. thinking of something to do with it would have been another. but I digress...

CD tower of seven 6x speed scsi drives ... thinking of something to do with it

The ability to have all seven install CDs in my SuSE Linux server.

Right now my workaround to avoid going into my basement to swap CDs is going to be a DVD-Rom for the box, and using the DVD version of SuSE 8.1 when I build the new server.