Scanner to USB 1.1 or 2.0 - speed ?

  • Thread starter Thread starter Bob
  • Start date Start date
B

Bob

I have a Canon 1250UF hooked up to an older USB 1.1 port. I am
considering installing a 2.0 card in the machine to speed up scanning.
But, I am wondering if it makes any practical difference.

Question: does the scanner adjust its actual scan speed to reflect the
USB interface it is attached to? Or does it scan at the same speed
regardless of what type of USB it is hooked up to ? The scanning
process does seem s little slow, but I have nothing to compare it to.
But, once the scanner has made the run across the document, the actual
"transfer" and appearance on the machine it is hooked up to is
instantaneous.

So, will a USB 2.0 connection actually speed the scanning process?

Thanks,
 
The 1250 is an older model, and a slower one. I have one here that has run
on both 1.1 and 2 USB. I saw a very slight improvement in scan speeds on
USB2, but not enough to get very excited about.
 
Bob said:
I have a Canon 1250UF hooked up to an older USB 1.1 port. I am
considering installing a 2.0 card in the machine to speed up scanning.
But, I am wondering if it makes any practical difference.

Question: does the scanner adjust its actual scan speed to reflect the
USB interface it is attached to? Or does it scan at the same speed
regardless of what type of USB it is hooked up to ? The scanning
process does seem s little slow, but I have nothing to compare it to.
But, once the scanner has made the run across the document, the actual
"transfer" and appearance on the machine it is hooked up to is
instantaneous.

So, will a USB 2.0 connection actually speed the scanning process?

Thanks,
Click to expand...
Check the information that came with your scanner. It should say if
it's connection is USB2.0 or the older kind. Unless it's designed to
use USB2.0 then no, there's no point in doing the upgrade.
 
Check the information that came with your scanner. It should say if
it's connection is USB2.0 or the older kind. Unless it's designed to
use USB2.0 then no, there's no point in doing the upgrade.
Click to expand...

It is a USB 2.0. Will the scan process go any faster or just the final
transfer after the scan is done ? ('cause the second part is not
slow).
 
Bob said:
It is a USB 2.0. Will the scan process go any faster or just the final
transfer after the scan is done ? ('cause the second part is not
slow).
Click to expand...

I don't have a definitive answer, but this is how I might approach
getting one, using engineering knowledge.

USB 1.1 has a maximum transfer rate of 12 Mb/s. Assume 10 bits are sent
for every byte, and not 8, to allow for a bit of overhead. That gives
USB 1.1 at 1.2 MB/s maximum. The average will not be as high as the
peak, but I might expect it to be half the peak, so say 0.6 MB/s.

Now if you transfer a 12 MB file, at 0.6 MB/s, I might expect that to
take about 20s via USB 1.1. If the scan is taking much over 20 s when
transferring a 12 MB file, then it is not being limited by the USB bus,
but by some other mechanism.

If the scan time is close to what you would expect the bus is capable
of, then it might be limited by the bus. It could however just mean the
bus and mechanics are well matched in speed.


--
Dave K

http://www.southminster-branch-line.org.uk/

Please note my email address changes periodically to avoid spam.
It is always of the form: month-year@domain. Hitting reply will work
for a couple of months only. Later set it manually. The month is
always written in 3 letters (e.g. Jan, not January etc)
 
Bob said:
I have a Canon 1250UF hooked up to an older USB 1.1 port. I am
considering installing a 2.0 card in the machine to speed up scanning.
But, I am wondering if it makes any practical difference.

Question: does the scanner adjust its actual scan speed to reflect the
USB interface it is attached to? Or does it scan at the same speed
regardless of what type of USB it is hooked up to ? The scanning
process does seem s little slow, but I have nothing to compare it to.
But, once the scanner has made the run across the document, the actual
"transfer" and appearance on the machine it is hooked up to is
instantaneous.

So, will a USB 2.0 connection actually speed the scanning process?

Thanks,
Click to expand...

Hi Bob...

The scan isn't at all related to the transfer after the scan is
finished.

The order of operations is - tell the scanner to scan now (virtually
instantaneous). Then the scanner does its mechanical scan. Finally
the scanners internal firmware does its thing. Then the result
is transferred to your computer.

The bottom line is that you won't see (again, virtually) any improvement
in upgrading to 2.0.

Take care.

Ken
 
Hello Bob,

I work at Fujitsu with document image scanners (ADF scanners). The
typical USB scanners that we have will capture 25 pages/minute simplex
or 50 images/minute duplex with a single pass.. (2 CCD's simultaneously
capturing as each page feeds through. The CCD's are 24 bit color and
600 true optical resolution so there's quite a bit of data transfer
between scanner hardware and your pc.

But, I'll say that USB 2 won't impact your performance vs. USB 1.1. The
likely "bottleneck" is with your pc processing the data. (in some
cases, the scanner hardware -depending on if your scanner has a
hardware JPEG compression board or not; or how much cache memory is
onboard the scanner...

If you want to see improvements in performance times, increase your RAM
or CPU (processor). RAM alone will make the biggest difference in most
cases.

Just thought I'd add my 2 cents...

~Danny
 
Back
Top