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Discussion Starter · #1 ·
I just recently bought a USB to serial (RS232) port adapter as well as a USB to
parallel (IEEE-1284) port adapter. I need them to connect a development
microprocessor board and debugger module to my laptop for one of my current
classes. The usb to serial adapter works great and does just what it is supposed to
do, which is to create a virtual serial COM port through USB. The parallel port
adapter however did not come with XP drivers, instead it relies on the native XP
driver "usbprint.sys", which works only if you want to install a parallel port
printer. I don't want to hook up a printer though, I just need it to create a
virtual LPT port so that the debugger can communicate with the software.

The driver cd came with drivers for Win 98/ME, however. I have inspected the .inf
files and I can tell for sure that they do what they are supposed to, by creating a
virtual port, not just printer support. I have tried everything I could to get XP
to use the 98 driver, but for some reason it won't let me update the driver to the
older one. The .inf file's version signature says "$CHICAGO$" which means it should
work on XP also, but windows tells me that it doesn't contain information about my
hardware (which is total bs). The USB vendor ID and product ID matches the device,
which is what really doesn't make sense as to why I would get that error.

So I what I need to know is if it is possible to disable the native xp driver
"usbprint.sys" for the device, or more likely somehow force windows to install the
98 drivers. I really just need to know how to get windows to properly identify the
driver file as a proper match for the hardware.
There are no other drivers for this
device, I've looked everywhere, and all say that XP supports it out of the box. So I was
hoping someone would be able to help. I can paste the inf files in here if it will help. Thanks

I'm running win xp pro on an HP dv2000t laptop with centrino duo cpu.
 

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You may be out of luck with that adapter. I find USB adapters for serial and parallel ports are far from universally compatible with some applications. You'd be better off with something like this EPP Parallel PCMCIA Cards.
 

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Ugh! :)

I guess there's always the docking station for your laptop...
 

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Discussion Starter · #5 ·
Well I did find this but I don't think you can buy it anywhere. Either it just came out or it's only available in Russia because that company is Russian.

Anyway, I've got good news. I was just messing around with the driver some more and I was able to modify the INF file so that it would recognize the device! It was only a matter of typing a USB/ in front of the product and vendor ID. I figured out how to do it by using some driver developer software to generate an INF file that would recognize the device but not actually provide a driver. So I compared to the two files and saw that it was the only real difference between the two file structures. So now windows installs the driver and creates a virtual LPT port (LPT3). I have yet to test the cable with a device but I have very good reason to believe it will work.

For future reference I will paste the modified parppl.inf text here
;
; This file is the Parallel port visual driver of USB to Parallel port
; Driver Name : PARPPL.vxd
; Inf Name : parppl.inf
; Copyright (c) Prolific Technology Inc., 2000
;

[version]
signature="$CHICAGO$"
Class=Ports
ClassGUID={4D36E978-E325-11CE-BFC1-08002BE10318}
Provider=%Vendor%

[DestinationDirs]
DefaultDestDir = 11

; Install class "Ports"
;----------------------------------------------------------
[ClassInstall]
AddReg=PortsClass.AddReg

[PortsClass.AddReg]
HKR,,,,%PortsClassName%
HKR,,Icon,,-23

; Drivers
;----------------------------------------------------------
[Manufacturer]
%Prolific%=Prolific

[Prolific]
%*ProlificPort.DeviceDesc%=USB2ParPort,USB\VID_067B&PID_2305

; USB2ParPort sections
;----------------------------------------------------------
[USB2ParPort]
AddReg=USB2ParPort.AddReg

[USB2ParPort.AddReg]
HKR,,DevLoader,,*vcomm
HKR,,PortDriver,,PARPPL.vxd
HKR,,PortSubClass,1,00
HKR,,ECPDevice,1,01
HKR,,USBDriver,,PARUPL.sys

[*ProlificPort.det]
AddReg=USB2ParPorts.AddReg

[USB2ParPorts.AddReg]
HKR,,NoSetupUI,,1

; User readable strings
;----------------------------------------------------------
[Strings]
Vendor = "Prolific"
Std = "(Standard Commumication Ports)"
PortsClassName = "Communication Ports (COM & LPT)"
Prolific = "Prolific"
*ProlificPort.DeviceDesc = "USB to Parallel Port"
DISK1 = "USB to Parallel Port Installation Disk"
 

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Hi,
I have also bought a USB to parallel converter to drive a set-up. Thank you, Ben, for your contribution.:up: I have done the modification on Parppl.inf and on the device manager, there is a virtual parallel port (LPT3).
To drive my set-up I was using the function Out32 () from Inpout32.dll. One of the parameter that this function need is the address of the parallel port.
Do you think that I can still use this function? If yes, I can do it, what is the address that I should use?:confused:
Thanks!
 

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Discussion Starter · #7 ·
After messing around with the drivers and getting windows to report the adapter as a LPT port, it still does not function as an actual port would. I did some research and found out that the hardware on the adapters only emulates the functions of a parallel port for the print functions (of course they fail to mention this on any packaging). The chipset on the adapter will never fully emulate a parallel port. I found the information on this page - http://www-user.tu-chemnitz.de/~heha/bastelecke/Rund um den PC/USB2LPT/index.html.en
The guy that runs that site also sells an adapter that does actually emulate a a parallel port. There's info on there that may help.
 
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