Discussion:
USB to parallel port converters
(too old to reply)
Neil Youngman
2007-11-27 13:05:01 UTC
Permalink
I have a Mustek 1200CP parallel scanner, which appears to be supported by
SANE, but no parallel port on my system. I do have a USB to parallel port
converter, which works fine with my printer, but I can't get it to recognise
my scanner.

sane-find-scanner -p -vv /dev/usb/lp0 doesn't find any scanners. Is there
something else I should try, or won't it work with a converter?

Neil Youngman
Neil Youngman
2007-12-08 14:20:20 UTC
Permalink
Post by Neil Youngman
I have a Mustek 1200CP parallel scanner, which appears to be supported by
SANE, but no parallel port on my system. I do have a USB to parallel port
converter, which works fine with my printer, but I can't get it to
recognise my scanner.
sane-find-scanner -p -vv /dev/usb/lp0 doesn't find any scanners. Is there
something else I should try, or won't it work with a converter?
No answer to this so far. Should I just give up?

Neil
Julian Stacey
2007-12-08 14:50:34 UTC
Permalink
Date: Sat, 8 Dec 2007 14:20:20 +0000
Post by Neil Youngman
I have a Mustek 1200CP parallel scanner, which appears to be supported by
SANE, but no parallel port on my system. I do have a USB to parallel port
converter, which works fine with my printer, but I can't get it to
recognise my scanner.
sane-find-scanner -p -vv /dev/usb/lp0 doesn't find any scanners. Is there
something else I should try, or won't it work with a converter?
No answer to this so far. Should I just give up?
I'm no scanner/sane specialist, but do remember a printer will even
work with a unidirectional parallel port, data just going computer
to printer, whereas a scanner feeds a lot of data back, (PC BIOSes
have various EPP/ECP etc modes, some modes support nibble mode too,
ie 4 bits each way for a PL-IP connection etc), So maybe your USB
to parallel device may need to support bidirectional (if it can), &
may need to be told to configure itself in bidirectional mode etc.
How you might set about doing that I cound't advise, but
would depend on your device manufacturer & which Unix you are using,
& whatever it's USB control vagaries might be. Good Luck !
--
Julian Stacey. Munich Computer Consultant, BSD Unix C Linux. http://berklix.com
Ihr Rauch = mein allergischer Kopfschmerz. Dump cigs 4 snuff.
Neil Youngman
2007-12-08 17:14:15 UTC
Permalink
Post by Julian Stacey
Date: Sat, 8 Dec 2007 14:20:20 +0000
Post by Neil Youngman
I have a Mustek 1200CP parallel scanner, which appears to be supported
by SANE, but no parallel port on my system. I do have a USB to parallel
port converter, which works fine with my printer, but I can't get it to
recognise my scanner.
sane-find-scanner -p -vv /dev/usb/lp0 doesn't find any scanners. Is
there something else I should try, or won't it work with a converter?
No answer to this so far. Should I just give up?
I'm no scanner/sane specialist, but do remember a printer will even
work with a unidirectional parallel port, data just going computer
to printer, whereas a scanner feeds a lot of data back, (PC BIOSes
have various EPP/ECP etc modes, some modes support nibble mode too,
ie 4 bits each way for a PL-IP connection etc), So maybe your USB
to parallel device may need to support bidirectional (if it can), &
may need to be told to configure itself in bidirectional mode etc.
How you might set about doing that I cound't advise, but
would depend on your device manufacturer & which Unix you are using,
& whatever it's USB control vagaries might be. Good Luck !
It's an unbranded adapter from ebay, so all I know is what dmesg tells me.

drivers/usb/class/usblp.c: usblp0: USB Bidirectional printer dev 2 if 0 alt 0
proto 2 vid 0x4348 pid 0x5584
usbcore: registered new driver usblp
drivers/usb/class/usblp.c: v0.13: USB Printer Device Class driver

and what I get from cat /proc/bus/usb/devices

T: Bus=02 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2
B: Alloc= 0/900 us ( 0%), #Int= 0, #Iso= 0
D: Ver= 1.10 Cls=09(hub ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=0000 ProdID=0000 Rev= 2.06
S: Manufacturer=Linux 2.6.18-5-amd64 uhci_hcd
S: Product=UHCI Host Controller
S: SerialNumber=0000:00:1d.1
C:* #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr= 0mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub
E: Ad=81(I) Atr=03(Int.) MxPS= 2 Ivl=255ms

That doesn't tell me much. I suspect it's more about the hub than the adapter?

I would be surprised if the adapter didn't support bidirectional ECP/EPP
modes, but I could always be wrong. It was advertised as a printer adapter.
There may be some modes required for scanners that it doesn't support,
however I suspect that the problem is more likely to be SANE assuming that
parallel port devices are only found on parallel ports and not on USB. Does
anyone know if this is the case?

Neil
Steve Underwood
2007-12-08 17:39:43 UTC
Permalink
Post by Neil Youngman
I would be surprised if the adapter didn't support bidirectional ECP/EPP
modes, but I could always be wrong. It was advertised as a printer adapter.
There may be some modes required for scanners that it doesn't support,
however I suspect that the problem is more likely to be SANE assuming that
parallel port devices are only found on parallel ports and not on USB. Does
anyone know if this is the case?
Neil
Then be prepared to be surprised. A USB serial gadget is a close
emulation of a traditional serial port. A USB parallel gadget is not
even vaguely similar to a traditional parallel port. The huge latency of
USB means it would be impractical for it to work in the same way. This
is a huge pain for a wide range of industrial gadgets, embedded
development tools, and other gizmos which only work with a PC's parallel
port. Even if you try written a custom for the USB gadget, the latency
makes it useless for almost anything.

Regards,
Steve
Neil Youngman
2007-12-08 18:27:51 UTC
Permalink
Post by Steve Underwood
Post by Neil Youngman
I would be surprised if the adapter didn't support bidirectional ECP/EPP
modes, but I could always be wrong. It was advertised as a printer
adapter. There may be some modes required for scanners that it doesn't
support, however I suspect that the problem is more likely to be SANE
assuming that parallel port devices are only found on parallel ports and
not on USB. Does anyone know if this is the case?
Neil
Then be prepared to be surprised. A USB serial gadget is a close
emulation of a traditional serial port. A USB parallel gadget is not
even vaguely similar to a traditional parallel port. The huge latency of
USB means it would be impractical for it to work in the same way. This
is a huge pain for a wide range of industrial gadgets, embedded
development tools, and other gizmos which only work with a PC's parallel
port. Even if you try written a custom for the USB gadget, the latency
makes it useless for almost anything.
People seem to be able to able to get scanners working on USB, so I guess
you're saying that the USB to parallel port conversion can't be made to work
adequately for bidirectional transfers?

Neil
Jochen Eisinger
2007-12-08 18:31:37 UTC
Permalink
Hi,
Post by Neil Youngman
I have a Mustek 1200CP parallel scanner, which appears to be supported by
Better buy a new scanner :)
Post by Neil Youngman
sane-find-scanner -p -vv /dev/usb/lp0 doesn't find any scanners. Is there
something else I should try, or won't it work with a converter?
lp0 is a printer device. So I guess you have an parallel port printer to
usb printer converter. That can't work with the scanner.

I don't know whether there is something like 'generic parallel port over
usb'.

Better buy a new scanner.

regards
-- jochen
Vidar Sæterbø
2007-12-08 20:00:50 UTC
Permalink
Post by Jochen Eisinger
Better buy a new scanner.
Something like this is probably cheaper:
http://www.amazon.com/Startech-com-PCI1PECP-Parallel-Card-1-port/dp/B00006B8BS/ref=sr_1_2?ie=UTF8&s=pc-hardware&qid=1197143803&sr=1-2

Or something secondhand off eBay...


Cheers
Vidar

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