Re: Interfacing to parallel port dongle via USB adapter

Paul E. Schoen wrote:
I have software (PADS Layout) that requires a parallel port dongle, and it works fine on my present (fairly old) computer, which has a native parallel port. But newer computers, particularly laptops, do not have these legacy ports and instead use USB to Parallel (or USB to Serial) converters. They generally work well for printers, but I have heard that they do not work for dongles. The usual solution is to obtain a USB dongle from the software vendor (www.mentor.com), but they require the user to be on "maintenance" in order to get a USB dongle, and they impose outrageous penalties and payment of back (unused) support in order to be reinstated.

I have some experience with USB using the Microchip PIC18F2450 series, and I have a demo board that works nicely as a USB to Serial converter. But I want to see if it is possible to emulate a parallel port via USB that will be transparent to the software that interfaces with the dongle. I think the problem with the commercially available USB-Parallel adapters is that they work only for printer functions, and not for individual bit-banging, which is what I understand is done with the dongle.

The PADS dongle I have is a Globetrotter FLEXid (www.macrovision.com). This is a newer dongle than the one used for another software package that interfaces to software (TCC) sold by my associate to work with my product, the Ortmaster. When I researched that dongle, the Rainbow Technologies Sentinel Pro, it described its operation as using only one or two lines of the parallel port to send and receive streams of data. If the new dongle works the same way, it seems that it should be possible to emulate this via USB.

Info on this device: http://www.macrovision.com/webdocuments/PDF/FLEXidDongle_faq.pdf. But it does not give details on the hardware.

Some information I found is http://www.woodmann.com/crackz/Dongles.htm, but this is a hacking site, and that is not what I want (although I'm tempted).

I'll probably check the parallel port signals with a storage scope to see what pins are active when I'm running the software with the dongle, and then I'll have a little more information. But if anyone has done any work in this area, I'd appreciate a jump start.

TIA,

Paul



Unfortunately, I suspect you won't have any success attaching a security dongle to a USB-to-parallel adapter. USB carries data in 1 millisecond frames, except for high speed where 125 microsecond frames are used. And any USB-parallel adapter will not be high speed, so the slower 1 millisecond packet timing will be applicable.

The parallel port hardware is mapped into the PC I/O space, and access is not constrained on any descrete time boundaries. So, if the dongle driver writes something to the dongle hardware and expects a response in tens to hundreds of microseconds, it will be impossible for the USB-parallel adapter to respond.

Your best bet is to purchase a PCMCIA/PCCARD parallel port adapter. Although they are a bit pricey ($100+ USD), they *should* be a faithful emulation of the hardware port. You might have to change the port/interrupt addresses to match the legacy addresses of 378h/278h/3BCh for the driver software to see the port (depends on how old your dongle software is). For a desktop machine, you should still be able to buy a PCI parallel port card for $30-$40 USD.

If you can reverse engineer your hardware key (and you are a legitimate owner of the software), then maybe you could write a kernel level driver that would emulate the parallel port. I'm a hardware guy and I don't know diddly about writing kernel level drivers - so this last suggestion may not be realistic. I have done some looking at dongle communication, and they much more sophisticated than the old Xilinx days of the 'AA', 'AB', and 'AC' hardware keys, which were easy to duplicate (only requiring some CMOS counters and gates).

Urb
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