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Unformatted text preview: r second. You can connect single-function units (mice, printers) or compound devices having more than one peripheral sharing the same port. A USB hub,
shown in Figure 2–12, is a compound device connected to several other devices, including other
When a device is attached to the computer via USB, the computer queries (enumerates) the
device to get its name, device type, and the type of device driver it supports. The computer can
suspend power to individual devices, putting them in a suspended state. For More BS-IT Books, Notes & Assignments visit: www.bsit.zxq.net 2.4 Components of Downloaded From:
a Typical x86 Computer www.bsit.zxq.net 51 Parallel Port Printers have traditionally been connected to computers using parallel ports.
The term parallel indicates that the bits in a data byte or word travel simultaneously from the
computer to the device, each on a separate wire. Data is transferred at high speed (1 MByte per
second) over short distances, usually no more than 10 feet. DOS automatically recognizes three
parallel ports: LPT1, LPT2, and LPT3. Parallel ports can be bidirectional, allowing the computer to both send data to and receive information from a device. Although many printers now
use USB connectors, parallel ports are useful for high-speed connections to laboratory instruments and custom hardware devices.
Figure 2–12 USB Hub Configuration.
B Scanner B A Hub A B A B Printer A
Camera B B Hub Device ATA Host Adapters Known as intelligent drive electronics or integrated drive electronics,
ATA host adapters connect computers to mass-storage devices such as hard drives and CDROMs. The letters ATA stand for advanced technology attachment, referring to the way the drive
controller hardware and ﬁrmware are located on the drive itself. ATA adapters use a common
interface named IDE (integrated drive electronics) found on all motherboards.
SATA Host Adapters SATA (serial ATA) host adapters have become the most common storage interface for laptop and desktop computers, replacing IDE and ATA interfaces. With only...
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- Winter '13