Parallel port to IDE cable standard?

Question

For parallel port to IDE devices, known as parallel IDE, I am wondering if there is a parallel cable standard? Or if standard parallel cables should work?

Background: A friend bought an Imation LS-120 SuperDrive. It's an IDE parallel model. Unfortunately, it only came with a power supply and a short drive dongle for parallel. It didn't include a full parallel cable to actually connect it to a parallel port. The dongle looks to be a micro centronics to parallel port adapter. So cannot be plugged into a parallel port directly and must be plugged in through a cable. It looks like a later model where they moved some electronics outside.

I managed to source a straight through D25M to D25M parallel cable I had hoped would work. So that I can actually plug it into a parallel port. But I cannot get it to work.

So this makes me wonder if there is a parallel cable standard for IDE that needs specific wiring or electronics or it simply will not work. Given the dongle is customised for that model leads me to believe it used a propriety parallel cable as well. But I cannot find any information on any parallel standards with modified wiring.

Testing: To confirm the drive does work I connected it without data cables to power supply. The drive turns on. When a disk is inserted it reads it. When ejected it pops it out. So basic drive mechanism is working.

When I connect it up and plug the parallel cable into a parallel port the drive goes dead. When switched on the drive acts dead. If I the unplug the cable from the parallel port it works again. It also works if just the dongle is connected. So for some reason it doesn't actually like being plugged into a parallel port.

Unfortunately I am limited with what computer hardware I can test it with. A desktop PC under the desk has no parallel port or I would have let Windows figure it out. The only computer I have with a parallel port is an uncommon PPC board based on a MAI Teron. I did however compile a custom Linux kernel with paride modules included to test. But they could not detect any device. I had hoped if there was some software protocol needed the driver would do what it needs to do and switch the drive on. But I saw no change. It uses epat protocol.

Conclusion: Apart from concentrating on the LS-120 my question was about generic parallel to IDE. Though each has parallel protocol is different. But the question remains if parallel to IDE cables have their own standard with internal electronics or electrical characteristics?

Answer 1

That board will not convert IDE to parallel. It has no components to do that.

It's simply an adapter to bring out the IDE interface to an external connector, to be used with an USB to IDE adapter with a matching connector.

EDIT:

As confirmed by the model of your drive, it came with a special active adapter with electronics powered by the drive in the drive connector, and it also splits to two DB25 connectors for inserting the drive between PC and a printer.

So basically, the USB and Parallel versions are identical with IDE interface on a custom connector. The adapter cable makes it a parallel or USB model.

You are lucky if the wrong adapter did not damage the drive, power supply, or the computer.

Answer 2

There is a guide on ifixit for this device that shows some better pictures that demonstrate how the drive is supposed to work. Look particularly at the images for step 2, which shows the back of the drive with the "USB converter" cable attached to it. That cable has a very chunky connector containing the actual conversion electronics.

The circuit board in your photo merely provides a robust, external connector that's wired straight through to the drive. The (correct) cable that attaches to that connector contains the appropriate conversion electronics. USB is perhaps the most common conversion cable, but you may see some that attach via SCSI or PCMCIA as well. This design makes the devices easier to manufacture, since the complicated, expensive portion (the drive itself) is the same for all product variants and they only have to throw a different cable in the box depending on which interface they're targeting. Likewise, the manufacturer can re-use the same conversion cables for different types of drive (IDE CD-ROM, etc).

The cable you show is a fairly standard cable for converting between two common styles of parallel port. It matches the connector on the back of the drive, but the drive's connector is not a parallel port. It uses the same physical connector but electrically it's still an IDE interface. Up through the 90's, it was sadly common for manufacturers to use existing connectors for completely incompatible purposes (I've seen at least a half dozen different uses for the 25-pin D-sub connector normally used on parallel port printers). I see two possible explanations for this cable:

1. The drive's seller didn't know much about the drive. They just saw the cable, thought "this must go with the drive since the connectors match", and threw it in the box. You'll need to find a proper cable in order to make this drive work. Here's a better picture of what you're looking for.
2. This drive was one of the earlier designs that used a separate ISA card for the conversion electronics. The cable in that case was a simple pass-through.

Given the unusually short length of your cable, option #1 seems more likely.

Instead of trying to find the matching cable for that proprietary connector, you may have better luck ditching the adapter board altogether and using trying a standard IDE-to-USB cable attached directly to the drive.