USB-parallel cable

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I've lost the cable for an old Acer parallel port scanner that I
haven't used for years. I've seen ads on eBay for USB-parallel
cables. Do they work? *Can* they work?

USB and parallel ports use such different techniques that I can't
see how such an adapter cable would work without some form of
interfacing. The price of the cables are so low (~$4US),
especially for a low-demand product, that it would seem to
preclude the inclusion of interfacing hardware.

Re: USB-parallel cable

Pimpom wrote:
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But that isn't the nature of the problem.

A USB cable of that type, is referred to in the advertisement
as a "USB printer" cable. And that is because, by design,
Microsoft only has a printer protocol stack available for it.

A printer port is bidirectional, and from a hardware perspective,
USB supports both reading and writing, so either direction of
protocol could be supported. Over the years, people have written
all sorts of programs, that talk to the parallel port and do bitwise
or nibble mode operations. None of those will work with the USB
cable, because it isn't the same kind of bus, as the bus used
for the older parallel port.

I presume, someone could write a fancy emulation software, to trap
accesses to a phantom parallel port, and translate them into USB
operations. But I'm not aware of anyone doing it yet.

The closest you might come, to full operation, would be
the addition of a card to the computer, with a parallel port
on it.

If the only thing you're interested in, is connecting is a printer,
then the USB cable for that might work. The scanner would probably
have its own driver, which would be attempting to reach a hardware
parallel port at a particular I/O address. For that, I would be
looking for a hardware card and cable, instead.

This is an example of a current generation parallel port card (for desktop).
I can't find any reviews, where someone has used a device, other than
a printer, with the card. So no feedback on all modes of operation
is available.

The chip used on that card is a MOSCHIP MCS 9901.

    "The Parallel Port interface is IEEE 1284
     compliant and supports SPP/PS2/EPP/ECP
     modes and Centronics interface."

Driver support listed on the datasheet, shows up to Vista support,
leaving us to guess whether they've written a Windows 7 driver.

At $20, at least that particular card represents a cheap experiment.


Re: USB-parallel cable

Paul wrote:
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I knew about add-on PCI parallel port cards and my interest in
the USB-parallel cable was really an academic one. This one from
an Indian online shop looks good.:

I'm in India and have dealt with these people before. The price
of 385 plus 55 shipping in Indian currency, equivalent to about
$8.30 + 1.20 US is more than OK. I would have been happy with
just the parallel port. The inclusion of 4 USB 2.0, 1 COM, 1
IEEE1394 and SATA ports will be a welcome bonus to those who need

Re: USB-parallel cable

On 10/01/2010 02:50 AM, Pimpom wrote:
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Won't do you any good without the cable
just get a new one

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