Is this a parallel port dongle that's required to run certain old software (w/out modification)? If so, how do I determine for what software or publisher it is for, assuming it is possible to do so?

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    One little-known item this might be is a Parallel Port Buffer, meant for adding buffer memory for dot matrix line printers. I have only seen one in real life, and it added 256kb to an otherwise bare device. The only modern mention I found was a reference to a "BF-50" Turbo device, however, I used to see them in supplier catalogs for computer stores. If there is a Phillips 74LVC1284 IC on that board, I bet it is your monster.
    – PhasedOut
    Oct 1 '18 at 19:29
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    Is there any branding on it at all? Most dongles and nearly all helpful devices had at least a logo.
    – Chris H
    Oct 2 '18 at 10:35
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    Are there any details you know that could narrow it down? How did you get it? Did it come with an old computer? eg if you know the operating system or relative power of the machine or what it was used for then it might help. Without at least a bit more info, it's going to be virtually impossible to identify. You might also try asking on retrocomputing.stackexchange, as they may have some additional insights that could help you.
    – Spudley
    Oct 2 '18 at 12:27
  • Can you remove the plastic cover from the opposite side?
    – PhasedOut
    Oct 2 '18 at 21:29
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    It may be possible to dissolve the epoxy potting compound and reverse-engineer the dongle if you need to - or just see if there's any manufacturer's mark on the PCB.
    – John U
    Oct 3 '18 at 10:33

Is this a parallel port dongle that's required to run certain old software (w/out modification)?

That's certainly what it looks like. The use of potting epoxy (in the third picture) is a strong indicator that the manufacturer of this device was trying to prevent reverse engineering -- I wouldn't expect to see that in a simple adapter, for instance.

If so, how do I determine for what software or publisher it is for, assuming it is possible to do so?

This is unlikely to be feasible. The way that these dongles operated was (intentionally!) nonstandard and obscure. If you were able to identify how this specific one operated and read data from it, it's possible that it might contain data identifying the software which it applied to -- but this would be a significant hardware reverse-engineering effort, and might still turn up nothing if the dongle doesn't contain any stored data, or if the manufacturer didn't embed any obvious identifiers in that data.

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    Or it is one of the few standard ones that have a key inside that could be used by multiple software manufacturers.
    – PlasmaHH
    Oct 1 '18 at 10:26
  • @PlasmaHH If it were one of the standard types, I'd expect the construction to be a little nicer. The two-part plastic case on this one looks like the sort of thing you'd use to build a dongle on the cheap, using only off-the-shelf parts.
    – user89623
    Oct 8 '18 at 3:17
  • why would it? Even back then people wanted to squeeze out every cent, and by using a standard case you don't have costs to develop that. Just slap a sticker on it and be good. I have seen dongles of similar quality for 6 figure software packages...
    – PlasmaHH
    Oct 8 '18 at 6:41

I seriously doubt you could figure out what it's for. I've written for such things before--we did not manufacture them, we bought them from the companies that do. There was absolutely nothing about the outside that indicated they were ours. We were small enough we didn't print special labeling for them.

The only way to figure out what they were was to try to talk to them. Provide the right key and they would answer. Our name didn't even appear internally, the only way to figure out whose they were would be the company that made them--they would know the contact information associated with the ID burned into the key.

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    @Xen2050: They had passthrough ports simply to avoid inconveniencing customers: computers rarely had more than one LPT port, and the customer very often already had a printer that they wanted to keep using. (Especially if the key was for text processing or graphics editing software!)
    – user1686
    Oct 1 '18 at 8:52
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    @Xen2050: As for how they worked, I'm sure it varies between different manufacturers, but you can start by researching one popular model – the parallel-port HASP keys by Aladdin (later SafeNet, now Gemalto). The modern USB license keys are all cryptographic, but I think I've heard of some LPT keys that were just basic EEPROM chips, though others weren't.
    – user1686
    Oct 1 '18 at 8:54
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    @KlaymenDK I have a vague memory of having a second parallel port on the Sun tower which acted as a server for our office in the early 90's. (We had two printers attached to it.) Oct 1 '18 at 9:06
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    @KlaymenDK: Well, there are PCI and ISA parallel port cards... (If I recall, MS-DOS already supported LPT2: and LPT3: just in case you had them.)
    – user1686
    Oct 1 '18 at 9:07
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    @KlaymenDK: "Multi-I/O" cards that provided one parallel port and two serial ports were commonplace, as were display cards that included a parallel port. If one had a display card with a parallel port but no serial ports, used a multi-I/O card to add a couple serial ports, one would then have two parallel ports.
    – supercat
    Oct 1 '18 at 19:08

I've got something identical to this knocking about somewhere, but it was for, ahem, circumventing copyright protection back in the day. It worked with software called Synchro Express (version 2 point Zero, Copyright Coast To Coast Technology, All Rights Reserved) on the Amiga.

You plugged a second floppy drive into it and it allegedly enabled the user to copy copy-protected games from DF0: to DF1: by duplicating byte-for-byte. I'm not sure it was ever that successful in reality though.

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    That's completely unrelated to this device. A byte-level copier is about bypassing (or duplicating) deliberate defects on a floppy disk that would prevent a system-level copier from making a disk copy that would pass the copy-protection check. This device is a copy-protection dongle: the software will refuse to run if this isn't plugged into the computer.
    – Mark
    Oct 1 '18 at 21:30
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    To be fair to @ThisLeeNoble it does look very much like a Synchro Express or X-Copy dongle. The biggest difference is that those devices had 23 pins (Amiga, Atari floppy cable) while this one has 25 pins. Very similar function. Oct 2 '18 at 4:25
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    As no one has said it yet: @ThisLeeNoble welcome to Super User!
    – Synoli
    Oct 2 '18 at 12:26
  • You might want to consider adding a picture; obligement.free.fr/gfx/amigasynchroexpress2_1.jpg. This looks almost identical, albeit with the label removed.
    – Valorum
    Oct 2 '18 at 19:38

Rainbow Sentinel Pro and KeyLok were Parallel Port Key dongles I worked with in the 80's. I think there was one called DESLock too but it was a long time ago. These all required you to communicate to them using some sample code provided by the dongle provider (in my case it was some C code which was compiled to .OBJ and linked into a Clipper application).
Without the code, the device is pretty much useless.


Well, I know this device, it's called HARD-LOCK,I'm a designer civil engineer and I used this in 90's to unlock a concrete software calculation and design. It was plugged on parallel port of a PC, I think it works sending some information from the software installed in a PC into hard-lock then hard-lock sends back doing a confirmation that the software has permission to run, different way for Autocad which uses KEYS like Windows to unlock the software.


I used one of these in the 90s on simulation software. The manufacturer was one of the hot-shot crypto companies (don't remember the name). The software would query the dongle once in a while and, if the response was accepted, the software would continue running normally. If the dongle was missing or didn't respond in time, the software would, IIRC, stop or switch to demo mode (deliberately crippled). A line printer could be hooked up to the dongle.


Looks a lot like a DB25 null modem, but I don't think that it is based on the resistors inside enter image description here

  • 1
    The odds of this being a null modem adapter is HIGHLY unlikely. Null modem adapters have no reason to be potted - covered in epoxy to hide its contents). Potting devices such as these is almost exclusively used in copy protection dongles to prevent them from being reverse engineered.
    – Keltari
    Feb 27 '19 at 18:30

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