Peripherals

PERIPHERAL DEVICES
Tory Klementsen, MCPA+
Sno Isle Skills Center

What is a peripheral?
 ??
 Name some peripherals we use every day.
 Name some peripherals that we might see in
business, but not necessarily in the consumer
world.
 What are some things technicians might do
with peripheral devices?

What is a
Peripheral
Understand the
differences
between
consumer and
business
peripherals
Understand
tasks
technicians
might do with
peripheral
devices?
Understand
what
peripheral
devices need
to operate
Learning Targets

Peripherals
 A peripheral is a hardware device that is controlled
by software but is not part of the core architecture of
the computer.
 It either expands a computers capacity or
capabilities.
 You must install both the hardware and the
software.
 Most all peripherals require the following basic
fundamentals:
 The hardware and firmware for the peripheral
 A device driver, BIOS, or both
 Available resources (IRQ, DMA, I/O address, memory
addresses)*

Peripherals, cont.
 Some peripherals also require proprietary
software that works in conjunction with the
device driver.
 Some devices will also have firmware
 Switches
 Routers
 Phones
 Tablets*

How the CPU Talks to the
Peripheral
 The CPU uses INT (interrupts) to locate an entry in the
interrupt vector table.
 This table, located in the lowest part of memory, stores
the address of an interrupt handler, a program that will
handle the request.
 The program is either a device driver or BIOS and will use
I/O addresses to communicate with the device.
 Some devices may connect to a controller that manages
the resources for it and other devices connected to the
controller.
 PCI, USB, IEEE 1394 (FireWire)*

Hardware Devices
 Internal devices—cheaper, difficult for
average user to install
 External devices—more expensive, easier to
install because they install on a port that’s
already configured.*

Embedded BIOS on Devices
 Some devices have
 ROM chips with firmware that holds software
 RAM to use as temporary storage
 Their own processors

Using Ports and Expansion Slots
for Add-on Devices
 Most PCs have:
 Four or more USB ports
 2-6 PCIe slots
 New ones might have a
thunderbolt port
 4-8 SATA ports*

Using Ports and Expansion Slots
for Add-on Devices
 Older PCs may also have:
 One or two serial or COM ports,
 One parallel port or LPT port,
 One or two IEEE 1394 or FireWire port.
 These ports were usually located on an
expansion board with older computers while
they are typically built into the newer system
boards.

Using Serial Ports:
 Serial ports transmit data one bit at a time.
 All serial ports are male and may have either
9 (DB-9) or 25 (DB-25) pins.

Serial Ports
9 Pin Male Serial Port
15 Pin female game/MIDI port
25 Pin male serial port (aka DB25)

Serial Ports, cont.
 Serial ports have been around for decades.
 Can connect
 Modems
 Bar code readers
 Old mice
 Also known as RS-232 (this is the standard to
which it conforms)
 Requires the use of a UART chip
 A chip that changes the parallel communications
of the system bus to serial so the serial device can
communicate with the computer.*

Serial Ports, cont.
 Also known as communication ports
 Communication is bi-directional, also known
as Full Duplex
 Bits are sent one byte at a time down one
line, received one byte a time on a receiving
line
 Parallel also sends one byte at a time, but requires
8 lines for each byte
 Parallel ports are faster than serial ports, but in
other situations, serial communication is faster
than parallel communication.

The UART Chip:
 UART stands for Universal Asynchronous
Receiver/Transmitter chip.
 It establishes and controls all serial
communications
 Is also responsible for converting parallel data
bits from the system bus into serial data bits.
 The UART chip controlling the port is partially
responsible for the speed of the port. *

Infrared Transceivers:
 Wireless infrared devices require an infrared
transceiver that can connect directly to a serial or
parallel port.
 May be PnP or you may have to install manually.
 Some system boards provide a 5-pin connection
for its own proprietary IRDA-compliant infrared
transceiver.
 If so, the transceiver mounts on the outside of the case
with a wire going through a small hole in the case to
the 5-pin connector.
 You will need to disable COM2 serial port because the
transceiver uses the resources for that port.*

Using Parallel Ports
 Parallel ports designed for printers transmit 8
data bits at a time, parallel to each other.
 Cables should be no more than 15 feet, HP says
10.
 Although parallel ports were designed for
printers, today's bi-directional parallel ports are
also used for high-speed access to other external
devices.
 Parallel ports are female 25-pin DB connectors.*

Using USB Ports
 USB ports are configured by the OS, making
them easier to use.
 USB Standards
 USB 1.1=12 Mbps
 USB 2.0=480 Mbps
 USB 3.o=up to 4.8 Gbps
 How do I know if my computer supports USB
2.0?
 Open device manager and look for Enhanced USB
host controller *

USB, cont.
 A USB cable has four wires, two for data, one
for ground, and one to provide up to 5 volts of
power to the device. *

Using IEEE 1394 Ports
 Some system boards may contain IEEE 1394
or FireWire ports.
 These ports have two types of connectors: a
4-pin port that does not provide voltage to a
device, and a faster 6-pin port that does.

IEEE 1394, cont.
 IEEE1394 uses isochronous data transfer
which means that the data is transferred
continuously without breaks.
 Can support up to 63 devices on one channel.
 This real-time data transfer is ideal for
camcorders,VCRs,TVs, and digital cameras.
*

IEEE 1394, cont.
 IEEE1394 A, supports speeds of 100, 200, or
400 Mbps, allows cable lengths up to 4.5 meters,
and is hot-pluggable.
 IEEE 1394 B, will support speeds up to 3.2 gbps
and extend the maximum cable length to 100
meters.*

Thunderbolt:
 Developed by Intel and introduced into Apple
Macbook Pros in 2011
 Allows multiplexing of data lines from PCIe and
DisplayPort (on Macs) devices.
 One port supports up to six devices
 Thunderbolt on a Mini Display Port can only
handle 4 lanes of output at no more than 5.4 Gb
per second.
 With a thunderbolt port it’s 2 input/2 output at a
full 10 Gb per second.
 20 pins*

Thunderbolt:
 Max length 3 meters
 18 v bus power
 Originally conceived as optical, but switched to
copper to provide powered port
 There is a lot of technology in the cable itself, so
even if the device sending a message is “noisy” the
cable can clean up and mux and demux a signal
 1.0 named Cactus Ridge
 2.0 named Redwood Ridge
 Runs at 20 Gbps and will only be built into computers, not
into devices
 Supports 4K resolution on passthrough

Thunderbolt vs USB 3.0
USB 3.0 Super Speed Thunderbolt
Speed 4.8 Gbps 10 Gbs (inTB port)
5.4 Gbps in MDP
Power for devices 4.5 watts 10 watts
Cost $4.50 for 2 meter cable $50 for 2 meter cable
Download 25 GB movie 60-75 seconds 30 seconds
Ubiquity Common uncommon

Touchscreens
 There are three basic types of touchscreens:
 capacitive screen uses a thin electrically charged
layer placed over the monitor screen.When
touched, the charge moves from the capacitive
surface to the touching object.The screen location
of the touch is calculated and sent to the
computer.This method blocks some of the light
emanating from the monitor.

Touchscreens
 resistive screen uses a glass panel covered with
two metallic layers (one conductive and the other
resistive) separated by a very narrow gap and
mounted over the monitor screen.When the
screen is touched, the two metallic layers make
contact and that location is calculated.This type
of touchscreen also blocks some of the monitor's
light emanation.

Touchscreens
 surface acoustic wave screen places tiny matching
transducers across the screen surface from each
other (one to send and the other to receive).When
an object touches the screen surface, the signal is
interrupted and that location is then calculated.
This type of touchscreen does not visually impair
the monitor.

Using PCI Expansion Slots
 The PCI local bus supports up to four PCI
expansion slots on the system board.
 Used for fast I/O devices, PCI slots feature bus
mastering that assigns resources to the
jumperless PCI cards.
 Simply moving a card to a different slot
changes the resources. *

PCI vs PCI Express
PCI PCI Express
 Parallel Communications
 Transmits in half duplex
 Bandwidth on the bus is
shared with other PCI
devices (like a hub)
 Devices can talk to each
other, to some extent
 Serial Communications
 Each 1x lane in PCI express
can transmit in both
directions at once
 Each device gets its own
bandwidth (like a switch)
 Devices can talk to each
other and work together

SLI/Crossfire
SLI Crossfire
 Scalable Link Interface
 Nvidia
 Each card controls half the
screen
 *Alienware also has its
own technology, and is
working on a FOUR card
solution. Overkill?
 ATI
 Splits screen
 In half, each card does half
 In tiles, one card renders
every other tile
 Each card renders alternate
frames

Video Cards
 Creating an image out of binary data is a
demanding process.
 The graphics card first creates a wire frame
out of straight lines.

Video Cards
 Then, it rasterizes the image (fills in the
remaining pixels).
 Adds lighting, texture and color.
 For fast-paced games, the computer has to
go through this process about sixty times per
second.Without a graphics card to perform
the necessary calculations, the workload
would be too much for the computer to
handle.

Parts of a Video Card
 A: GPU (w/heatsink and
fan
 B: DVI-D digital
connector
 C: VGA, analog
connector
 D: Gold lead connectors
 E: VI/VO port (video
in/video out)
 F: Heatsinks covering
VRAM

Monitors
 Monitors have been called
 Cathode RayTubes (CRTs)
 Video DisplayTerminals (VDTs)
 CONsole (CON), which is the DOS device name;
 "the screen.“
 The two main categories of computer
monitors are cathode tube and Liquid Crystal
Display (LCD).

CRT
 A CRT (monitor) is a vacuum tube with an electron gun at one
end of the tube (the narrow end), and a large piece of glass at
the other end (the wider end).
 The inside surface of the viewing pane is coated with a layer
of dots made up of three different kinds of phosphor (a
chemical).
 The electron gun is made up of three different electron
beams.
 Each beam shoots a stream of electrons at the phosphors,
with each beam making one type of phosphor glow.
 When we look at the glass face of the monitor, we're actually
seeing through the glass to the backside of the phosphor
layer.
 In monochrome monitors, there is only one layer of
phosphors, either green or amber, and a single electron beam.

Measuring CRT
 Size—diagonal measure of the tube
 Resolution—Number of pixels on screen
horizontal x vertical
 Display type
 Shadow mask—metal screen full of holes
 Aperture grill—ultra thin wires in a mesh that is
brighter than shadow
 Aspect ratio: 4:3

Measuring CRTs
 Dot pitch—Distance between pixels, smaller
is better
 Refresh rate—Amount of time for CRT gun to
move from top to bottom
 Interlacing—Draws the screen in two passes,
evens then odds
 Green—less power
 Flat—flat glass, better picture

LCD
 Liquid crystals exist in either a solid or a near-liquid state, depending
on electrical conditions.
 In their near-liquid state, the crystals can pass light.
 Crystals have a tendency to be straight (like rods) in their natural
state, but they twist into a right angle under electrical stimulation.
 This capability of passing light when they're straight or turning at
right angles and blocking light gave rise to the LCD panel. (It wasn't
really alien technology, no matter what anyone tells you.)
 Liquid crystals rely on a background source of light to pass through
each crystal.
 If light can pass through the crystal, our eyes can see it.When the
crystal is turned off, it won't let light pass and we see an area of
black.
 Each crystal can be either on or off, much like binary computer
numbers can be either 0 (off) or 1 (on).

Plasma
 Each pixel is three fluorescent lights
 Fluorescent lights have plasma gas in them, hence
the name
 The colors are red, green, and blue
 A grid of cells makes up the screen
 Each cell contains gas
 The screen has phosphorous on it
 Electricity is applied and when there is a
differential, light lights up the phosphorous
and emits color.

OLED
 Organic light emitting diode
 Solid state
 Have thin films of organic molecules that
light up when electricity is applied
 Uses less light and less power than LCD and
CRT and Plasma
 Brighter and crisper
 Only a 14,000-230,000 hours of lifetime (red
and green is longer, blue is shorter)

Uses for OLED
 http://www.thinkgeek.com/computing/keybo
ards-mice/9836/zoom/
 http://www.tagtele.com/videos/voir/24766
 http://www.oled-display.info/etri-shows-
clothes-with-oled
 http://electronicdesign.com/Files/29/15993/Fi
gure_03.jpg

Common Issues
 CRT interference from EMI and magnetic
sources
 Degauss the screen to remove the magnetic field
from the screen
 Dead pixels (LCD)—very common. Most
manufacturers allow a certain number of
pixels

Peripherals

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