Speed limited by OS or cable?

  • Thread starter Thread starter Don Phillipson
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Don Phillipson

I was pleased with the Brother DCP 540CN installed upstairs
last Christmas, especially its scanning, speed, therefore added
downstairs a Brother 330C, mostly similar.

But the scanning speed is not -- it s as slow as the discarded Epson..
Is the reason
1. That the printer's scanning software runs Twunk_16.EXE
instead of TWUNK_32.EXE, also part of the Win98SE OS?
The upstairs PC runs WinXP so is presumably all 32-bit.
2. Or is it the USB cable? Having no new cable at home
I used the cable from a discarded Epson, the type with
lumpy cylinders at both ends, next to the terminal plugs.
What do those cylinders do anyway?
 
Don Phillipson said:
I was pleased with the Brother DCP 540CN installed upstairs
last Christmas, especially its scanning, speed, therefore added
downstairs a Brother 330C, mostly similar.

But the scanning speed is not -- it s as slow as the discarded Epson..
Is the reason
1. That the printer's scanning software runs Twunk_16.EXE
instead of TWUNK_32.EXE, also part of the Win98SE OS?
The upstairs PC runs WinXP so is presumably all 32-bit.
2. Or is it the USB cable? Having no new cable at home
I used the cable from a discarded Epson, the type with
lumpy cylinders at both ends, next to the terminal plugs.
What do those cylinders do anyway?
Click to expand...


Speed is limited by the USB speed and the OS.

Windows 98 Second edition only supports USB 1.1 speed, about 12 Megabits per
second.
And Windows 98 is probably a 16 bit system.

Windows XP probably has USB 2.0 ports and run at about 480 Megabits per
second.
Windows XP can be 32 bits or 64 bits.

The lumpy cylinders at both ends of the USB cable are RF filters. Or chokes.
They keep radio frequency interference out.
 
Speed is limited by the USB speed and the OS.
Windows 98 Second edition only supports USB 1.1 speed, about 12 Megabits per
second. And Windows 98 is probably a 16 bit system.
Click to expand...

Sorry, this seems unlikely. Win98SE supports USB.v.2 (that is why
SE appeared) and is largely a 32-bit OS (with leftover 16-bit modules
to run older software.) This PC earlier ran a 32-bit Umax scanner at
OK speed.

It so happens our WinXP PC has only USB.v.1 (which it announces
whenever I connect an external USB drive) yet its Br.540 CN scans
fast. This was why I asked about the Twain modules as the
likely indicator of slow scanning There are only three references
to Twunk_16.EXE in Registry so perhaps I shall write in 32 in
case that helps.

Thanks for explaining cylinders on Epson cable as RF filters.
 
"Don Phillipson"
Sorry, this seems unlikely. Win98SE supports USB.v.2 (that is why
SE appeared)
Click to expand...

Not arguing,
just supporting Carl in that I could never get USB2 on my 98se, just 1.1
That's why I went to XP.
I am surprised if what you say is correct.
 
rodney said:
"Don Phillipson"

Not arguing,
just supporting Carl in that I could never get USB2 on my 98se, just 1.1
That's why I went to XP.
I am surprised if what you say is correct.
Click to expand...
98se (and ME) have no built in drivers for USB2.0, but that doesn't mean it
won't run USB2.0, it just means you must use third party drivers for those
ports. XP with SP1 does have USB 2.0 built in. Of course the hardware on
the PCs must support USB 2.0 to be able to utilize those drivers, just
changing drivers won't magically make USB 1.1s into 2.0s. Windows 95
version C was the first Windows O/S to include USB 1.1 drivers.

If your XP PC really does only have USB 1.1s, get a PCI USB 2.0 card.[/QUOTE]
 
rodney said:
"Don Phillipson"

Not arguing,
just supporting Carl in that I could never get USB2 on my 98se, just 1.1
That's why I went to XP.
I am surprised if what you say is correct.
Click to expand...
98se (and ME) have no built in drivers for USB2.0, but that doesn't mean it
won't run USB2.0, it just means you must use third party drivers for those
ports. XP with SP1 does have USB 2.0 built in. Of course the hardware on
the PCs must support USB 2.0 to be able to utilize those drivers, just
changing drivers won't magically make USB 1.1s into 2.0s. Windows 95
version C was the first Windows O/S to include USB 1.1 drivers.

If your XP PC really does only have USB 1.1s, get a PCI USB 2.0 card.[/QUOTE]
 
Don Phillipson said:
... downstairs a Brother 330C, mostly similar.
But the scanning speed is not -- it's as slow as ...
...
2.  Or is it the USB cable?
Click to expand...

The specs for the DCP-330C on the Brother site says:
"USB 2.0 Full speed"

2.0 "Full speed" in USB-speak is the standard USB 1.1 max rate,
and not 2.0 "High speed" which is the 480Mbps/8MB rate.

The USB logo for the product on the Brother pages also
omits the red "HIGH SPEED" tailfin on top, consistent
with the device being "Full Speed" only.

Full speed is nominally 12Mbps/1.5MB, but according to
a driver developer I used to work with, unless the device
games the spec (IDs as multiple endpoints) it only ever
gets half that, and somewhat less in real scenarios due
to overhead.

In Win9x testing I did comparing a USB 1.1 scanner to it's earlier
Async SCSI sibling, both nominally 1.5MB/sec devices, I got
4.8Mbps or 600KB/sec on the USB, and around
8Mbps/1.0MB (IIRCC) on the SCSI.

On a flat bed scanner for which 300 dpi is an integer fraction
of the native res, an 8x10 24-bit color scan, with no on-board-
-scanner compression, would be a 21.6MB object, and would
take 36 seconds to scan at 600KB/sec. That your ballpark?

If so, using a 2.0 cable on a 2.0 interface and a 2.0 USB
driver for 98SE won't help. And yes, the USB 2.0 "Full Speed"
branding is dodgy.
 
On a flat bed scanner for which 300 dpi is an integer fraction
of the native res, an 8x10 24-bit color scan, with no on-board-
-scanner compression, would be a 21.6MB object, and would
take 36 seconds to scan at 600KB/sec. That your ballpark?

If so, using a 2.0 cable on a 2.0 interface and a 2.0 USB
driver for 98SE won't help. And yes, the USB 2.0 "Full Speed"
branding is dodgy.
Click to expand...

Test results are the same with two USB cables tested,
Epson brand USB 1.1 and new no-brand USB 2.0
Test image for scanning is 2500 x 1150 pixels in 24-bit
colour, scanned at 300 x 300 dpi, image thus about 9 Mb.

Brother DCP 540CN under WinXP (SP2) running at 1.6 GHz:
this PC has only USB v.1.1. Default Brother installation has
two scanning options:
TW = Twain and ScanSoft PaperPort software: scans in 14 seconds
WIA = Windows Image Acquisition scans in 20 seconds.

The Brother DCP 330C (very similar to 540CN without
networking hardware) installed under Win98SE (with USB.v.2)
running at 2.8 GHz. Its Brother (Paperport) software takes 2 min. 14s
i.e. 134 sec. to scan the image.

NB: The Win98 PC has both TWUNK_16.EXE and TWUNK_32
which looks like 16-bit and 32-bit software. While scanning
Ctl Alt Del (process manager) tells me TWUNK_16 is loaded
i.e. not 32-bit Twain. This may explain the difference. I would
rather know how to fix it i.e. make Paperport use the 32-bit
Twain module. Ought I to be looking for other scan software?
 
Don Phillipson said:
Test image for scanning is 2500 x 1150 pixels in 24-bit
colour, scanned at 300 x 300 dpi, image thus about 9 Mb.
Click to expand...
Brother DCP 540CN under WinXP (SP2) ...
TW = Twain and ScanSoft PaperPort software: scans in 14 seconds
Click to expand...

That's 616 KB/sec, and is consistent with operating at
USB 1.1 max speed, or USB 2.0 "full" speed.
WIA = Windows Image Acquisition scans in 20 seconds.
Click to expand...

Mr.Bill's hackers must be making lots of call to the
Waste_Time_On_Old_CPUs()
routine supplied to them by Intel to motivate upgrades. :-)
The Brother DCP 330C (very similar to 540CN without
networking hardware) installed under Win98SE (with USB.v.2)
(Paperport) software takes 2 min. 14s
i.e. 134 sec. to scan the image.
Click to expand...

That's only 64KB/sec, which suggests a problem somewhere.
It is, curiously, about what I'd expect if the port or device was
operating in USB "low speed" mode (1.5 Mbit/s (187.5 kB/s).

Another possibility is that due to system performance and
overhead, the scanner is unable to stream, and is reverting
to a stop-start mode, which could easily be a stop-backup-start
mode, which could easily degrade throughput to 64K.
Ought I to be looking for other scan software?
Click to expand...

I've stopped running Win9x at my home, due to the security risks
(and the inability to easily get back to a last-patch level due to
the lack of WindowsUpdate support), not to mention inability to
get Win9x compatible apps, including scanning. Your choices may
be limited.
 
The lumpy cylinders at both ends of the USB cable are RF filters. Or chokes.
They keep radio frequency interference out.

--
CSM1http://www.carlmcmillan.com
--- Hide quoted text -

- Show quoted text -
Click to expand...

Hummh.

All along I thought they were inductors to compensate for the
capacitance of the cable/wiring or to compensate for the length of the
cable to improve the bandpass.

Bob AZ
 
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