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Diagnostics
USB Device Drivers
The ability to hot swap USB devices is a great feature, but it relies on a somewhat oversimplified set of
general-purpose drivers. Some devices may appear to be general-purpose devices when in fact they are
not. This means that you must install the drivers before you connect the device to the PC. Sometimes you
need to reboot to give the new drivers priority over the general-purpose drivers. This means that skipping the
reboot will break the whole process.
If you think the new drivers aren’t receiving priority, completely uninstall the device in question. You may
have to leave the device connected to uninstall it properly. At other times, you may be able to remove a
device’s drivers using Control Panel’s Add/Remove Programs applet, just as you would with other software.
Sometimes it’s necessary to upgrade a device’s firmware, which is basically a driver that runs on the periph
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eral. The more advanced the device, the more likely it is that the firmware can be upgraded. Mice, being
simple devices, don’t require firmware upgrades. Scanners, hard disks, printers, optical disks, and other
sophisticated peripherals likely have upgradeable firmware. Check the manufacturer’s site to ensure you’ve
loaded the most recent update.
Bandwidth
USB root hubs can each support up to 128 devices, but they can run out of bandwidth, depending on con-
sumption rates. USB 1.1 is limited to 12 Mbps, not counting the bus management overhead. USB 2.0 has
480 Mbps with about 420 Mbps available, so it can support more devices. Combine an Ethernet adapter,
a printer, and an external CD-ROM or hard drive on a single USB controller, though, and the PC can quickly
exhaust its capacity.
The only solution for bandwidth problems is to either stop using all the devices simultaneously or to distribute
the load. Make sure you put devices that will always see use, like Ethernet adapters and USB speakers, on
different root hubs. You may need to get additional USB controllers, which are inexpensive.
Содержание UHR Ultra
Страница 1: ...Service Manual Ultra UHR Ultra and V3400 WHEEL ALIGNER May 2014 ...
Страница 13: ...11 AC DC POWER DISTRIBUTION ...
Страница 14: ...12 AC DC POWER DISTRIBUTION ...
Страница 16: ...14 Theory of Operation Figure 2 Top Field of View Figure1 Side Field of View ...
Страница 19: ...17 Theory of Operation Configuration using single pole wheel clamp ...
Страница 46: ...44 NOTES ...
Страница 67: ...65 Diagnostics ...
Страница 68: ...66 NOTES ...
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Страница 84: ...05 07 2014 2014 Impreso en U S A 309 Exchange Avenue Conway AR 72032 TEEWA546P4 Rev C ...