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kony
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 Posted: Mon Jun 16, 2008 10:51 am Post subject: Re: Front Panel USB Headers - some devices dont work |
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On Sun, 15 Jun 2008 02:53:18 -0700 (PDT), sandy58
<aleckie68@googlemail.com> wrote:
| Quote: |
On Jun 15, 6:20 am, BigAl...@gmail.com wrote:
Hi All,
I have come across this once or twice and its never really bothered
me, but I am curious as to why:
Occasionally I fond certain devices wont work on front panel usb
headers, yet when plugged into the rear USB connectors that are "hard
wired" to the motherboard, they are fine.
At the moment, I have two external HDDs (with there own power supply)
that wont work on the front but do work on the rear, however various
other devices such as mouse and USB thumb drives do work on the front.
Why????
Cheers
-Al
PS: seen it on both XP and Vista.
I'm with kony on this. I never use a front end usb access for that
reason. Mostly junk & blow anything shoved in there. 
|
I do use them, with mixed results. One time I had to finish
up a case and had no USB2 spec round cable at the time (was
an old case I moderized by cutting a square hole to mount a
USB port), and used a ribbon cable. At the time, USB2
didn't exist yet (except maybe on paper) so the cable was
sufficient for USB1, but later the case innards were
moderized with a board having USB2.
I never got around to swapping out the ribbon cable with a
rounded one because it's not a primary use system and the
system would need more modifications if it were every
upgraded again due to insufficient airflow and no easy way
to add that (old Gateway case that was double-walled with a
curved plastic exterior, it's just not worth the extra
work). That front port works fine with USB2 thumbdrives,
but the signal is degraded a lot apparently as performance
is only 60% or so of what the same thumbdrives get
otherwise, and these are not particularly fast drives, the
performance would probably go down more if they were.
Even on a fairly new Coolermaster case with what looks like
a decent quality round cable, benchmarks show about 10%
performance reduction using the front panel ports instead of
rear with a newer USB flash thumbdrive, but this is a small
enough difference that I don't mind so much, as flash drive
performance has practically doubled over the last 2-3 years
and it's not even worth the bother to reach over further to
plug it into a motherboard rear port connected USB hub
unless I've a lot of files to move.
I find scanners and printers to be the more problematic USB
connected devices when it comes to failure to detect and
use, whether it be when the drivers for the device are
initially installed or later when one tries to use the
device and the system can't find it. This is assuming the
motherboard uses 5V instead of 5VSB for USB port power, if
it doesn't the first thing I try is 5V instead, and
connecting to a hub or other system which often reveals a
poor cable that came with the device can be swapped to make
it work, on most if not all systems and ports but the front
panel case ports still seem to cause problems more often
than the rear ones. It'll be interesting to see if the
problem gets better (even resolved), worse, or stays similar
when USB3 and supporting products are released. |
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Paul
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| Posted: Mon Jun 16, 2008 11:02 am Post subject: Re: Front Panel USB Headers - some devices dont work |
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kony wrote:
| Quote: |
On Sun, 15 Jun 2008 11:44:15 +0100, "ded"
witheld@invalid.witheld> wrote:
The wimp known as gazwad, being KM's arse licker contributed
"Gazwad" <nospam.spam.nospam@gmail.com> wrote in message
news:wewjgz$pxo$t@servile-happiness-
I'll keep it brief,
You may as well, you bullshit-spouting retard.
it is a type of "remembering" so that once a device
is connected, that device hogs that connection. The front panel USB
is a type of hub, so if you are going to connect differing devices at
differing times, then disconnect using the safely remove hardware
wizard that appears in system tray when a device is connected to
front panel or a hub. It doesn't remove drivers or anything else,
it just frees up the socket for next device to be connected.
Shakes head
Is it too puzzling for you, you don't understand the difference between
the rear panel USB being a PCI card and the front panel being a basic
powered on board hub, you didn't know that?
It's no excuse for "Gazwad's" reply, but most front panel
USB is not a powered on board hub. Most is just an
extension cable from the motherboard pin headers. An
exception would be when that does to a multi-in-one modular
device like a card reader that has more than one integral
USB socket or more than one other device integrated that
uses USB besides the card reader slots.
|
The ports come from the Southbridge, because the Southbridge
has a ton of them available, and no motherboard makers wastes
money adding chips which are not needed. The Southbridge handles
ports on the I/O area on the back of the computer, and sends signals
to the spare 2x5 headers on the motherboard surface (intended for
extension cables and PCI slot covers and for front panel USB ports).
In some cases, Southbridge USB ports are used to control onboard
Wifi devices or sound devices. There is generally no need for
a hub on the motherboard. The Southbridge does it all.
The best quality signals electrically, will be the signals
that travel through the motherboard PCB, and go to the
USB stacks on the back of the computer. If an external USB
device is having problems, use the connectors on the back
for best results.
To give an example of how the quality of the computer case,
fits into all of this, consider what Antec was doing with
their computer cases years ago. They shipped a front panel
assembly, which was only compatible with USB 1.1. The company
knew exactly what they were doing, which was screwing their
users. You could connect a USB2 capable motherboard to the
Antec case, and the ports would only work in USB 1.1 mode. If
you complained to Antec, they would send out a new USB2
compatible module, to fit into the front panel. That is
an example, of how the properties of the cable and
front panel module, can affect how a front connected USB
device works (or doesn't work).
USB2 is a high speed interconnect, with requirements on
cable impedance and shielding. This is an example of a tool
that engineers use, to verify proper USB2 operation. A home
builder cannot afford to do this kind of testing, so there
is no way to know how well a front mounted USB port is working.
In the figure here, the blue lines are an "eye diagram", and the
red portions are the "template". To pass, the blue part, cannot
touch the red part. The red part is the "specification" and
the blue part is collected from thousands of measurements of
logic 1's and 0's on the USB connector (the device making the
measurement and display, is a digital storage oscilloscope).
A similar technique is used to verify that DVI works on your
video card.
http://www.testequity.com/productprint/1181/
Paul |
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kony
Guest
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| Posted: Mon Jun 16, 2008 4:49 pm Post subject: Re: Front Panel USB Headers - some devices dont work |
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On Mon, 16 Jun 2008 02:42:42 -0400, Paul <nospam@needed.com>
wrote:
| Quote: |
It's no excuse for "Gazwad's" reply, but most front panel
USB is not a powered on board hub. Most is just an
extension cable from the motherboard pin headers. An
exception would be when that does to a multi-in-one modular
device like a card reader that has more than one integral
USB socket or more than one other device integrated that
uses USB besides the card reader slots.
The ports come from the Southbridge, because the Southbridge
has a ton of them available, and no motherboard makers wastes
money adding chips which are not needed. The Southbridge handles
ports on the I/O area on the back of the computer, and sends signals
to the spare 2x5 headers on the motherboard surface (intended for
extension cables and PCI slot covers and for front panel USB ports).
In some cases, Southbridge USB ports are used to control onboard
Wifi devices or sound devices. There is generally no need for
a hub on the motherboard. The Southbridge does it all.
|
I was under the impression what was being referred to, and
what I'd replied to, was present of a hub on the front panel
I/O card. |
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Paul
Guest
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| Posted: Mon Jun 16, 2008 6:31 pm Post subject: Re: Front Panel USB Headers - some devices dont work |
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kony wrote:
| Quote: |
On Mon, 16 Jun 2008 02:42:42 -0400, Paul <nospam@needed.com
wrote:
It's no excuse for "Gazwad's" reply, but most front panel
USB is not a powered on board hub. Most is just an
extension cable from the motherboard pin headers. An
exception would be when that does to a multi-in-one modular
device like a card reader that has more than one integral
USB socket or more than one other device integrated that
uses USB besides the card reader slots.
The ports come from the Southbridge, because the Southbridge
has a ton of them available, and no motherboard makers wastes
money adding chips which are not needed. The Southbridge handles
ports on the I/O area on the back of the computer, and sends signals
to the spare 2x5 headers on the motherboard surface (intended for
extension cables and PCI slot covers and for front panel USB ports).
In some cases, Southbridge USB ports are used to control onboard
Wifi devices or sound devices. There is generally no need for
a hub on the motherboard. The Southbridge does it all.
I was under the impression what was being referred to, and
what I'd replied to, was present of a hub on the front panel
I/O card.
|
The original post only mentions a cable, and no other details.
I'm assuming the cable has the usual small PCB and USB connectors
connected to the end of it. Sort of the functional equivalent
of one of these, only with the USB connectors poking out the
front of the computer case.
http://estore.asus.com/images/14-000500020.JPG
Paul |
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kony
Guest
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| Posted: Tue Jun 17, 2008 1:08 am Post subject: Re: Front Panel USB Headers - some devices dont work |
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On Mon, 16 Jun 2008 09:31:14 -0400, Paul <nospam@needed.com>
wrote:
| Quote: |
kony wrote:
On Mon, 16 Jun 2008 02:42:42 -0400, Paul <nospam@needed.com
wrote:
It's no excuse for "Gazwad's" reply, but most front panel
USB is not a powered on board hub. Most is just an
extension cable from the motherboard pin headers. An
exception would be when that does to a multi-in-one modular
device like a card reader that has more than one integral
USB socket or more than one other device integrated that
uses USB besides the card reader slots.
The ports come from the Southbridge, because the Southbridge
has a ton of them available, and no motherboard makers wastes
money adding chips which are not needed. The Southbridge handles
ports on the I/O area on the back of the computer, and sends signals
to the spare 2x5 headers on the motherboard surface (intended for
extension cables and PCI slot covers and for front panel USB ports).
In some cases, Southbridge USB ports are used to control onboard
Wifi devices or sound devices. There is generally no need for
a hub on the motherboard. The Southbridge does it all.
I was under the impression what was being referred to, and
what I'd replied to, was present of a hub on the front panel
I/O card.
The original post only mentions a cable, and no other details.
I'm assuming the cable has the usual small PCB and USB connectors
connected to the end of it. Sort of the functional equivalent
of one of these, only with the USB connectors poking out the
front of the computer case.
http://estore.asus.com/images/14-000500020.JPG
|
I agree, that is the usual way it is done, but I had replied
to the (quote) "the front panel being a basic powered on
board hub" since it is not commonly done that way. |
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Claude Hopper (11) 5. ?
Guest
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| Posted: Tue Jun 17, 2008 1:51 am Post subject: Re: Why breathing is good for you |
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Pennywise@DerryMaine.Gov wrote:
| Quote: |
somebody wrote this:
wat does masturbate mean?
you mean masturbator, it's a person who is a professional baiter.
Master Bates was that guy in Alfred Hitchcock's Psycho. |
--
Claude Hopper :)
? ? ¥ |
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