I currently have a ton of QIC-250MB tapes that I would like to read from (its been 30 years). I have a Tandberg TDC 3600 SCSI interfaced tape drive but I am lost how to connect it. In the past, with the computers then, they had a SCSI port where I could directly connect it. However, with computers today, SCSI interfaces appear to be obsolete. To be more specific, this is how it looks from the front:

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and from the back:

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The back looks like a 50 Pin Centronics. I am just not sure how I can connect such a device using modern computers, if at all. Any suggestions or guidances would be much appreciated! I am essentially starting from scratch, and would be interested in purchasing an old computer unit, if necessary. Finally, I have one of these iomega SCSI to USB adapters that were made back in the day. The interface on this looks like a SCSI-2 interface. Is there a way to perhaps convert the 50 pin HD to the SCSI-2 then to USB?

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Would something like this allow the IOMEGA to connect to the 50 pin internal without use of ribbons? enter image description here

EDIT (12-6-2019):

Thanks to all the comments. I ended up buying the adapter above and was able to get it working by connecting the drive to the adapter, then the iOmega adapter to convert to usb. The biggest thing was getting the terminator power correct. This was done by setting the pins in the drive correctly. The first drive I used wasn't able to be used since it was older and didn't have terminator power pin controls. The second drive did work. I actually then plugged the usb into my Macbook Pro, booted into a flash drive version of Linux (Ubuntu 18.04), and then used the mt command to control the tape drive and was able to read it all out.

  • SAS and FC (and iSCSI) is SCSI except with different electrical interfaces. iSCSI .... is well if FC is sane and easy to get working well ... iSCSI is well shall we say hard, so except for less well working USB-SCSI host adaptors the software situation on the computer side is shall we say not a problem... Commented Dec 7, 2019 at 20:05

2 Answers 2


The back looks like a 50 Pin Centronics. I am just not sure how I can connect such a device using modern computers, if at all. Any suggestions or guidances would be much appreciated!

Well, it seems to be a classic 50 Pin SCSI-1 interface - or at least compatible. So do it the same way it always has been done: Get yourself an SCSI interface card.

Jup, it's as easy as that, as there are SCSI cards are well in production, just nowadays for PCIe. I will not add any sellers, but just key in SCSI PCIe into your favorite search engine. Similarly, there are controllers for USB (try SCSI USB) or SATA (SCSI SATA).

Whatever fits your machine best. Costwise they are all in the 50 USD region. Well, brand new ones may be more than that, but then there is still the used market.

Edit, since you already found an USB to SCSI one.

The interface on this looks like a SCSI-2 interface. Is there a way to perhaps convert the 50 pin HD to the SCSI-2 then to USB?

SCSI-2 is exactly like SCSI-1, just with a double width data bus (*1). SCSI-2 introduced Wide SCSI with doubling the data path (thus needing more pins) and Fast SCSI which doubles the data rate - or both, Fast Wide SCSI, quadrupling the data rate.

In any case, they are all compatible, even different devices operating in either mode (Standard, Fast, Wide, Fast-Wide) can be combined at the same controller.

So all you now need is a 68 pin to 50 pin header (not Centronics) cable. More likely this will be two cables, 68 to 50 (Centronics) and 50 (Centronics) to 50 (Pin header).

You may want to check the manual for the adaptor, as it may as well be an Ultra SCSI one (also 68 pin). Not all SCSI-1 drives will be compatible, but more important, you may need a converting cable, as Ultra is using twisted pair cableing - and no terminators.

*1 - The wide part wasn't as often used, despite the connector.

  • Thanks for the answer. I have several SCSI to USB adapters (like the one above). Do you think there is a remote chance it could connect to a modern Linux or even Mac OSX computer via usb?
    – user321627
    Commented Nov 7, 2018 at 23:21
  • Sure, in most cases it should be a fairly automated process - ofc, depending on having the right USB driver - and you still need some driver for the tape itself. Linux might be a good choice to find some. On Mac Id rather go the way via an supported PCIe card.
    – Raffzahn
    Commented Nov 7, 2018 at 23:23
  • Thanks again. This is some great information you are imparting here. Just two quick questions, I am a bit confused where the 68 pin comes in, is it to connect the adapter or is it separate? Secondly, is termination an issue to be considered or should I try without worrying about it first? Thanks again, much appreciated!
    – user321627
    Commented Nov 7, 2018 at 23:26
  • Not sure what your confusion here is. The above USB adaptor has a 68 pin connector, so its SCSI-2. The Device is SCSI-1 with a 50 pin connector, so you need an SCSI cable that connects the 50 pin from the drive to the same 50 on the adaptor side, leaving the other 18 untouched. And yes, the last drive always need to be terminated. You may want to check the adaptors documenttion.
    – Raffzahn
    Commented Nov 7, 2018 at 23:50
  • I was under the impression the USB adaptor has 50 pins, if that is the case, would I still need a 68 pin connector?
    – user321627
    Commented Nov 8, 2018 at 8:02

The first thing you need to do is to open the front door of the drive and inspect the rubber roller that drives the tape. It is not uncommon for the roller on old drives to have deteriorated into a black goo. You don't want that stuff fouling your tapes.

Second, you need to inspect your tapes and ensure that the belts are still good. These belts develop dry-rot over time, and if they're broken (or so weak that they're likely to break when you read the tape) you will have problems.

Once that's done, your simplest path forward is probably to install a SCSI host adapter in one of the expansion slots of your computer. Try to find a card that supports single-ended SCSI, such a card will have the same 50-pin connector on the card and a simple ribbon cable will connect the card to the tape drive.

Another option is to find a SCSI enclosure for your tape drive, this will convert the internal ribbon connector to an external connector that you're more likely to be able to find a cable or adapter for.

Keep in mind that you will need to worry about software too. Once the drive is hooked up, how will you read from it? If your tapes were written using NTBACKUP.EXE (aka Windows Backup) then keep in mind that modern versions of Windows no longer include that utility. You may need to set up a retro system running older software to be able to read your tapes.

  • Thank you very much for your response. I did not think to check the belts yet, such an important thing to do! I have found something like an SCSI enclosure. Would you think the the following product: cablesdirect.com/store/p/2945.aspx would work? Would there be any voltage issues here in your opinion? thank you so much.
    – user321627
    Commented Nov 10, 2018 at 17:53
  • 1
    I don't see any reason why that adapter wouldn't work. I'd recommend detaching it from the faceplate of course. Voltage is unlikely to be a problem, as long as you get a SCSI host adapter that's "single ended" (SE) rather than "low voltage differential" (LVD). Since the connectors for SE versus LVD SCSI are different then it's a good bet you'll be fine as long as the connectors fit together.
    – Ken Gober
    Commented Nov 11, 2018 at 17:17
  • Thanks again, I'm curious if you have any thoughts to me trying to bypass the host adapter and directly connect the HPDB50 female side (after removing the faceplace like you mention) into the iomega scsi to usb adapter I have in the picture above. Do you think this will theoretically create issues? I am not even sure how to think about the voltage at this point. Thanks again!
    – user321627
    Commented Nov 11, 2018 at 21:14
  • In this context the Iomega adapter is the host adapter. The host adapter is the SCSI controller card, it's not something you can bypass. If the connectors fit you should be fine. Whether it will actually work depends on whether the Iomega adapter is a full SCSI adapter or whether it only supports certain Iomega drives, and on whether you have the needed software (drivers and whatever application software will recognize the data on the tape).
    – Ken Gober
    Commented Nov 12, 2018 at 12:55

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