Notes- CompTIA A+ (220-801).pdf

8/9/2019 Notes- CompTIA A+ (220-801).pdf

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CompTIA A+ (220-801)

Hardware 40%

BIOS/CMOS/POST

Boot Order

1. BIOS

2. Bootstrap

3. POST

4. CMOS

5. MBR (Master Boot Record)

a. stored in Hard Disk

6. OS (Operating System)

BIOS (Basic Input/Output System)

1stProgram activated during boot

Set of instructions

Stored in EEPROM chip on motherboard (used to be ROM)

Flashing BIOS (updating)

Run a software designed to re-write

Components of BIOS

Low level BIOS code POST

CMOS Setup Program

Boot order

Clock Speed

Memory installed

Hard disk size

BIOS Monitoring Capabilities

Enable/Disable devices

Set the date and time

Clock Speeds Enable/Disable Virtualization Technology

Virtualization is a CPU feature; not hardware

Go to CMOS Settings

o Enable VT (Virtualization Technology)

Enable/Disable BIOS security

Supervisor passwords

Admin Password


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prevents user from rearranging boot order

TPM (Trusted Platform Module)

provides a cryptographic hardware platform for securely storing data

lo-jack - locates where laptop is if its connected to internet

fan speeds

intrusion detection

voltage

bus speed

BIOS Chassis Intrusion

alerts when the computer is booted that the cover has been opened

POST (Power On Self-Test)

1. CPU

2. BIOS

3. BIOS Memory

4. Memory (RAM)

5. I/O Bus or I/O Controller

CMOS (Complementary Metal Oxide semiconductor)

Provides BIOS with info about the computer

Stores info such as hardware settings (time, clock, hardware inventory etc.)

Stored in RAM

CMOS Battery prevents data loss

o If batter is low = slow clock

o If batter is dead = checksum error during boot

UEFI

a replacement for BIOS CPU-independent

Flexible pre-OS environment

Offers greater security

Note:

EEPROM = Electronically Erasable Programmable Data

Firmware Programs on ROM

Software Programs on RAM


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Motherboard - Form Factor

Motherboard skeleton of computer

Connects everything together Form Factor Design of the Motherboard

ATX (Advanced Technology Extended)

Replaced AT + Baby AT

1. ATX (most popular)

12 x 9.6 inches (rectangle)

7 expansion slots

Full tower

2. Mini-ATX

11.2 x 8.2 inches

7 expansion slots

Full tower

3. Micro-ATX

9.6 x 9.6 inches (square)

4 expansion slots

Mini Tower

lowered cost of system by reducing number of expansion slots, smaller case

size, and reducing power supply requirement

4. Flex ATX

9.0 x 7.5 inches

4 expansion slots

Mini tower

ITX (no fan, low heat, low power requirements)

1. Mini-ITX

6.7 x 6.7 inches

2. Nano-ITX

4.7 x 4.7 inches

3. Pico-ITX

3.8 x 2.8 inches

4. Mobile ITX

2.9 x 2.9 inches

BTX was supposed to be successor of ATX but didnt due to incompatibility with newerchipsets and processors

Better cooling efficiency ; better airflow; quiet


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Motherboard Chipset

Chipset determines what CPUs a system can use and the number/type of expansion slots it can

hold

MCH (Memory Controller Hub)

Northbridge Used for high speed memory components (example: PCIe, AGP etc.)

ICH (I/O) Controller Hub)

Southbridge

Used for mass storage (example: PCI, CMOS, USB etc.)

Jumper group of 2 to 3 pins on motherboard or card

Used for configuration of settings

Jumper Block fits across 2 jumper pins to enable/disable feature

Can be used to reset/clear CMOS passwords

BSOD (Blue Screen Of Death)

STOP Error Causes reboots

Chip creep socketed chips loosening out of socket due to heat/cooling

Motherboard Expansion Slots

Expansion Bus - does not run in sync with system clock

Local Bus - runs in sync with system clock

1. PCI (Peripheral Component Interconnect

Network/ Sound/ Video/ SCSI cards

32-bit also 64-bit

33 MHz

132 MBps

uses 8-pin connector

2. PCI-X (PCI Extended)

Faster version of PCI; compatible with PCI cards

64-bit

133 MHz

PCI-X 2.0 266 MHz & 533 MHz

3. AGP (Accelerated Graphics Port)

Video Cards

32-bit

66 MHz

2X = 133 MHz

4X = 266 MHz


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8X = 533 MHz

has 2 interfaces

4. PCIe (PCI Express)

Replaced PCI & PCI-X & AGP; not backwards compatible

X1 & X4 = replaced PCI slot

X8 & X16 = replaced AGP and PCI-X

Usually black colored

Transfers data in lanes; one lane = X1

32 Gbps

can use 6 or 8 pin connector

5. AMR (Audio/Modem Riser)

Modem/ Sound connector

6. CNR (Communication Network Riser

Replaced AMR

Modem/ Network/ Sound

7. Mini PCI

Used for laptops; lies flat

Used for Bluetooth & Wi-Fi

Motherboard CPU and CPU Sockets

CPU (Central Processing Unit)

brain of computer

CPU speed - number of cycles per second; measured in Hertz

60 Celsius = CPU operating temperature

Hyper threading (HT Technology) Allows a single processor to act like multiple processors

Increased performance by 15% to 30%

to work, OS must support SMP (Symmetric Multiprocessing)

Multi Core

processor with two or more cores

If its a quad core or more, the software must support it for it to work faster

Dual-Core

Requires TLP (Thread-Level Parallelism) to work

GPU (Graphics Processing Unit)

Overclocking

running processor and other components faster Can be enabled for Processors & System Bus

Throttling

protects from heat damage by slowing the clock rate

VRM (Voltage Regulator Module)

module used to regulate the voltage fed to the CPU

MMX (Multimedia Extensions (MMX)

instructions called microcode, to support sound video and graphics multimeida functions


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Displays

CRT (Cathode Ray Tube)

Display screen coated with phosphor

electron gun shoots electrons at the phosphor, causing it to glow

Refresh Rate - speed that gun paints image across the screen

LCD/LED

1. LCD creates an image

2. Backlight illuminates the image

3. Inverters send power to the backlight

Native Resolution

Fixed resolution that cant go higher

QXGA (Quad Extended Graphics Array) Max Resolution: 2048 X 1536

Refresh Rate - how quickly/often the screen can change images completely

Standard: 60 - 120 Hz

Projector

Lumens - used to measure brightness of projector

Throw - image size at certain distance

Hard Disk

SCSI controller

8-bit bus: ID ranges from 0 - 7

Device with lower ID number has lowest priority

First boot device should be set to SCSI ID 0 Controller is ID 7

Hard Drive speeds:

5,400 rpm

7,200 rpm

10,000 rpm

15,000 rpm

Platter

Hard drives usually have multiple disks. Each disk is known as a platter

Spindle

Revolves the Platter

Display Connectors


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SATA

Serial ATA

smaller, faster than old parallel version

SATA revision 1.0

1.5 Gbps 150 MBps

SATA revision 2.0

3 Gbps

300 MBps

SATA revision 3.0

6 Gbps

600 MBps

eSATA

external connectivity

up to 6.6 feet

PATA Parallel ATA

Originally called ATA

IDE

8.3 MBps

EIDE

faster than IDE; concept of other devices

16.6 MBps

S-Video

4, 7 or 9 pins

VGA

3 rows, DB-15 connector

RAM

When program is opened in Windows, it is copied from Hard Drive to memory

At least one memory slot must have a module for system to function

Parity - error-detection method

ECC

DMA (Direct Memory Access)

Transfers data directly from hard drive to memory

So it doesnt interrupt CPU cycle (to slow it down)

SIMM - (Single Inline Memory Module)

one row of contact

no longer in use

72-pins

32-bit


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DIMM - (Dual Inline Memory Module)

two rows of contacts

168-pins

RIMM - (Rambus DIMM)

184-pins

heat spreader - metal jacket to dissipate excess heat

SODIMM - (Small Outline DIMM)

used in laptops

144-pins

MicroDIMM - (MicroDIMM)

used in laptops

DRAM (Dynamic Access Memory)

Dynamic - memory is recharged (electrically) to prevent data loss

SRAM (Static RAM)

used for cache

fast speed: 533 MHz example: PC200, PC300 etc.

RDRAM

Developed by Rambus

aka RIMM

has to be used in pairs

unused slots require CRIMM (Continuity RIMM)

300 or 800 MHz

184-pins

(PC600, PC700, PC800, PC1066, PC1200)

SDRAM (Synchronous DRAM)

Synchronous - runs in sync with the system clock

168-pins

2 notches

speeds of (PC66, PC100, PC133)

DDR SDRAM

184 - pins

1 notch

(PC1600, PC2100, PC2700 and PC3200)

DDR2 SDRAM

240-pins

1 notch

DDR3 SDRAM

requires 30% less power than DDR2

240 pins


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1 notch

12,800 MB/s

800 MHz

(PC3-12800) data transfer rate of DDR3 from the name DDR3-1600, simply multiply the 1600

by 8 (bytes) and solve for megabytes

To figure out the data transfer rate of DDR3 by the consumer name PC3-12800,just look at the number within the name and add MB/s to the end.

Optical Drives

Blu-Ray drives can play

Blu-Ray

CD-ROM

DVD

HD DVD drives can play CD-ROM

DVD

CD-ROM

can only play CD-ROM

CD

Storage: 700 MB

Speed: 1X = 150 KB/s

DVD

Storage: 4.7 GB

Speed: 1X = 1.32 MB/s

uses red laser

DL-DVD

Storage: 9.4 GB

Blu-Ray

Storage: 25 GB

Speed: 1X = 4.5 MB/s

uses blue laser; better focus

holds five time more data than DVD

holds up to 9 hours of HD video

holds up to 23 hours of SD video

Tape Storage: 800 GB

Floppy

Storage: 1.4 MB

Components: Read/write heads; stepper motor; circuit board

USB

127 devices can be daisy chained


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1 USB port can daisy chain 5 Hubs

4 pins

USB 1.1

12 Mbps

Cable length: 3 meters


USB 2.0 (most common)

480 Mbps


USB 3.0

5 Gbps

10 times faster than USB 2.0

USB Connectors

Type A

Type B

Mini-A Mini-B

FireWire

IEEE 1394a

FireWire400

400 Mbps

cable length: 4.5 meters

IEEE 1394b

FireWire800 800 Mbps

Can daisy-chain up to 63 devices

RAID

RAID 0

Total Drives: 2

Striping - total of two hard drives; data is striped

striping means the set of data is splitted, and a piece is stored in each drive RAID 1

Total Drives: 2

Mirror - duplicates the original disk to each drive

RAID 2

Total Drives: at least 3

Data is striped with parity

RAID 3


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Total Disks: At least 3

One Disk is used only for parity

Remaining disks are striped

RAID 4

Same as RAID 3 but uses block-level striping instead of byte-level striping

RAID 5


All disks appear as one disk

Parity is across all disks

All disks are striped

RAID 10


mirrored stripe sets

Power Supply

Plugging in 20-pin power supply into a 24-pin connector on motherboard:

Leave pins 11, 12, 23 and 24 unconnected

These pins are for higher voltages

Voltage output by power supply unit in a PC

+3.3 volts

used by Chipsets, DIMM, PCI/AGP cards, Pentium processor

+5.0 volts

+12.0 volts

Power Connectors Molex

4 pins

Motherboard Connectors

PCI = 8-pin connector

PCIe = 6 or 8-pin connector

Floppy Drive = 4-pin connector

ATA Hard Drive = 4-pin

SATA Hard Drive = 15-pin

12 Mbps


USB 2.0 (most common)

Config Computers


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CAD/CAM Workstation - Powerful processor, high-end video, maximum RAM

Home Server - RAID array, Gigabit NIC

Home Theater PC - Surround-sound audio, TV tuner, HDMI output

Virtualization Workstation - Maximum RAM and CPU

Networking 27%

Network Cables & Connectors

Twisted Pair (unused LAN)

used for 10BaseT

STP (Shielded Twisted Pair)

Foil around each pair

less susceptible to interference

UTP (Unshielded Twisted Pair)

Susceptible to interference (fluorescent light)

4 pairs of twisted wires, 8 wires total

Categories (max Length: 100 meters; 328 feet)

CAT1 Standard telephone cable

CAT3 10 Mbps

CAT4 16 Mbps

CAT5 100 Mbps

o used with RJ-45 connectors

CAT5e 1 Gbps

CAT6 10 Gbps (55 meters) CAT6e 10 Gbps (100 meters)

Plenum - area above suspended ceiling

fire resistant cable

Coax Cable

Single core of copper

Used for Cable Modems, Cable TV and Modem-based internet connections

RG-49

Thinnet / 10Base2

Carries 10 Mbps of Ethernet data

Max length: 185 meters 50 ohm impedance

RG-6

Thicknet / 10Base5

10 Mbps

50-MHz or higher

Max length: 500 meters

75 ohm impedance


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RG-6/U

used for cable TV

75 ohms of impedance

Max length: 300 meters

Connectors:

F-type (most common)

BNC (older) screw by spinning on

75 oh impedance

Note:

Baseband (Base) - only one signal at a time is sent onto the network medium

Broadband - multiplexes the signals to allow multiple signals on the medium

Fiber-Optic Cable:

Shoots pulses of light

Multi-Mode (majority)

10 Gbps

500 - 600 meters uses LED (light emitting diodes) to send light signal

multiple sets of data at a time

Single-Mode

10 Gbps or 1 Tbps

uses Laser to send light signal

3000 meters - 40 km

one set of data at a time

Connectors

SC - Subscriber Connector (square)

used for singlemode

snap in ST - Straight Tip (round connector)

used for multimode

twist to latch

LC - (square)

used for singlemode and multimode

POTS (Plain-old telephone service)

has two twisted pairs of copper wire, total of 4 wires

used for telephone landlines

Network Topologies

Ring, Star, Mesh, Hybrid

(TCP/IP) - IPv4


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Installed by default on Windows; Mac OS X; Linux

TCP/IP is a collection of protocols

Every IP address is unique for each computer on the network

3 Major TCP Address settings

IP Address

Subnet Mask (Network/Host)

Default Gateway

IPv4

32-bit number

example: 131.112.199 (4 groups, separated by dots)

IP Classes

Class A: 1.0.0.0 - 126.255.255.255

255.0.0.0

Class B: 128.0.0.0- 191.255.255.255

255.255.0.0 Class C: 192.0.0.0 - 223.255.255.255

255.255.255.0

Default Gateway - required to connect two computers that are not on the same network

Public, Private, APIPA

Public - anything thats not Private or APIPA

Private (ranges)

10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255

192.168.0.0 - 192.168.255.255

APIPA

assigned when a valid IP is not received by DHCP

169.254.0.1 - 169.255.254.0

By default, built into Microsoft Windows

Disable in Registry

used for troubleshooting

Loopback address is 127.0.0.1

used for testing

(TCP/IP) - IPv6

128-bit


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example: 2001:cdba:0000:0000:0000:0000:3257:9652 (8 groups, separated by colons)

Some of the header fields have been dropped

less rigid length limits and ability to introduce new options

Packets will indicate particular traffic type

Support will be provided for data integrity and confidentiality

Loopback Address ::1

(TCP/IP) Static vs Dynamic

Static

IP manually assigned

can only be changed manually

usually used for servers, routers, printers

Dynamic

IP automatically assigned by DHCP

DHCP - Dynamic Host Configuration Protocol

Valid for 3 days (limited time, then gets a new IP)

Protocols TCP & UDP

Port Number - specified service on a computer

TCP (Transmission Control Protocol)

offers guaranteed delivery service

needs verification of received data or else it will re-send UDP (User Datagram Protocol)

faster and better delivery

not guaranteed that it is received

used mostly with live streaming videos; VoIP calls

Faster than TCP

Network Ports

20/21 = FTP (File Transfer Port)

23 = Telnet 25 = SMTP (Simple Mail Transfer Protocol) - outgoing mail

53 = DNS (Domain Name System) - converts names from words to IP addresses

80 = HTTP (Hypertext Transfer Protocol)

110 = POP3 (Post Office Protocol) - incoming email

143 = IMAP4 (Internet Message Access Protocol) - Incoming email

443 = HTTPS (HTTP over SSL)

3389 = RDP (Remote Control Desktop)


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Basic Protocols

DHCP (Dynamic Host Control Protocol)

Protocol: UDP

Port: 67, 68

Function: Provides IP addresses

DNS (Domain Name System)

Protocol: UDP

Port: 53

Function: converts names from words to IP addresses & IP addresses to names

LDAP (Lightweight Directory Access Protocol)

Protocol: TCP

Port: 389

Function: Used to access directory information over IP addresses

SNMP (Simple Network Management Protocol)

Protocol: UDP Port: 161

Function Used to monitor networks

SMB (Server Message Blocks)

Protocol: TCP

Port: 445

Function: Provides access to files, printers etc. on a network

CIFS

SSH (Secure Shell)

Function: provides secure network

SFTP (SSH File Transfer Protocol)

Port Forwarding/ Triggering

Forwarding

sends incoming data/requests to a specific computer or device based on the port

number included in the request

The port must always be open and accept incoming traffic

Triggering

port forwarding that switches on and off

enabled only when internal machine initiates communication to a specific port

IEEE Standards

802.11a

Frequency: 5 GHz


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54 Mbps

Range: 20-45 meters

802.11b

Frequency: 2.4 GHz

11 Mbps

Range: 45 - 120 meters

uses WEP for security

802.11g

Frequency: 2.4 GHz

54 Mbps

Range: 30 -100 meters

compatible with 802.11a and 802.11b

802.11n

Frequency: 2.4 GHz or 5 GHz

600 Mbps

Range: 100 - 200 meters

MIMO - device can use multiple antennas

Compatible with 802.11b and 802.11g

Encryption

WEP (Wired Equivalent Privacy)

64-bit key

WPA (WiFi Protected Access

128-bit key

WPA 2

256-bit key (best encryption)

Encryption Protocol

TKIP

AES

replaced TKIP

used in WPA2

best encryption

Wireless Connections

Infrared

Line-of-Sight


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requires unobstructed view

RF (Radio Frequency)

802.11

Bluetooth

Networking Collisions

CSMA/CD (Ethernet)

Packets of data sent without checking network

if collision occurs, it will re-send

CSMA/CA (Wireless)

check for clear network first and then sends data

Network Types

WAN (Wide Area Network)

Group of one or more LANs

LAN (Local Area Network)

WLAN (Wireless LAN)

data transmission mode: half-duplex

MAN (Metropolitan Area Network)

PAN (Personal Area Network)

VPN (Virtual Private Network)

Protects communications sent through a public network

provides secure connections between endpoints such as routers, clients or servers byusing tunneling to encrypt data

Ad Hoc

network without connecting device such as hubs or switches or WAPs

clients communicate directly with each other

Internet Connection Types

Cable

Fiber ISDN (Integrated Services Digital Network

Connects multiple telephone devices to a single phone line

2 types;

PRI

BRI

DSL (Digital Subscriber Line)

replaced ISDN

Bandwidth: 300 Kbps


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requires telephone line

2 types

ASDL (Asynchronous DSL)

enables faster downloads/uploads

SDSL (Synchronous DSL)

DUN (Dial-Up Network)

Satellite

WiMAX

Wireless Internet in 4G rang

10 Mbps

Line of Sight

Cellular (mobile hotspot)

GSM (Global System Mobile Communications)

3G - 56 Mbps

4G - 100 Mbps

Verizon & Sprint

CDMA (Code Division Multiple Access)

T-Mobile & AT&T Client - computer with wireless network interface card (NIC)

NIC card uses RJ-45

Gateway - Translates data from one format to another

Server - computer on network that provides other computers access to resources such as disk

drives

Bluetooth

Frequency: 2.4 GHz to 2.485 GHz

Classes:

Class 1: 100 meters/ 300 feet

Class 2: 10 meters/ 33 feet

Class 3: 1 meter/ 3 feet Bluetooth 1.0

100 meters

Bluetooth 2.0

Distance: 10 meters

3 Mbps

Bluetooth 3.0

1 meter

24 Mbps

Network Devices

Hub - provides connectivity between devices

Switch - connecting device


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Router -

connects one LAN network to another; connects to outside network

Connects networks using the same protocol

Gateway -

hardware and/or software

connects networks that use different protocols

WAP (Wireless Access Point)

device where wireless signals are received/managed

PoE - (Power over Ethernet)

Bridge - connects two Lans, or splits a single LAN

Modem - converts digital signals to analog signals

dial up modem uses RJ-11

NAS (Network-attached Storage)

storage attached to the network

Firewall - controls/restricts and manages incoming/outgoing network (and phone numbers to IP)

VoIP phones - Converts analog signals to digital signals

Internet Appliance

Repeater - increase usable length of cable NAT (Network Address Translation)

allows a network of computers to appear to the Internet as a single entity

WPS

Wi-Fi Protected Setup

enables easy secure setup of small home networks

erases the setup of complicated config setting of wireless routers

comes installed on some routers and i enabled by default

vulnerable to brute-force attacks

Tools

Crimper - puts together RJ-45 connector to UTP cable

Multimeter - Measures voltage, current and resistance

Toner Probe - trace wires

Cable Tester - tests cable to see if it can make a connection

Loopback plug - to make loopback test; RJ-45; check signal

Punchdown Tool - aka krone; insert wire into connector

TDR (Time-Domain Reflectometer) - used to measure the length of the cable on the timerequired for an energy pulse to travel down the cable and return to the TDR

Standard Clients

Thick Client - 4Gb of RAM

has all components you would have on a regular workstation


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Thin Client - limited amount of storage on hard drive

small hard drive

files stored on network, not much on hard drive

has network connection

has browser

applications are stored on the server

2GB of RAM usually

Laptops 11%

Laptop Basics

To find capacity of the batter of a laptop

Wattage = Output Voltage x Output Amp

Desktop Replacement

Provides the capabilities and performance of a desktop

large and heavier than standard laptops

Sub Notebook

aka ultraportable

designed with an emphasis on portability

smaller display; no optical media drive

Netbook

extremely small, lightweight and energy efficient

Designed specifically for wireless communication and internet access

Laptops use LCD screens

Three Main Standard Resolutions

WXGA 1280 X 800

HD 1366 X 768

WSXGA+ 1680 X 1050

WUXGA 1920 X 1200

Battery

Li-Ion - Lithium - ion

provides highest energy density while maintaining the lowest self-discharge rate. will

retain power r the longest

NiCD - Nickel Cadmium

provides moderate energy density and self disraghe rate - shortest life


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NiHM - Nickel Metal-hydride

provides highest energy density but high discharge rate

Lead Acid battery has moderate energy density and self-discharge

Expansion Options

Five Main Expansion Options on Laptops

ExpressCard Basics

An interface allows peripheral devices to be connected to a laptop

Formally known as NEWCARD

ExpressCard is a standard specifying the design of slots in a computer and the cards that

can be inserted

ExpressCard Form Factors

/35

/54 Express Card /34

34 mm wide

26-pin

Express Card /54

54 mm wide

26 - pin

PCMCIA

Personal Computer Memory Card International Association

original name for PC Card (replaced by ExpressCard

three form factors called Types

Type 1

o 3.3 mm thick; 16 bit; RAM, Flash memoy

o 68 pins

o type 1 slot can only hold one Type 1 card

Type 2

o 5.0 mm thick; 16 or 32 bit; Modems, Network cards, TV tuner

cards, scsi controllers

o 68 pins

o hold one type 2 card or one type 1, or 2 type 3

Type 3

o 10.5 mm thick; 16 or 32 bit; Hard disk drive cards

o 68 pins

o one type 4 card or any comvination of two type 1 or 2 cards

SODIMM

Small Outline Dual Inline Interface

Half size of regular DIMM

pins: 72, 100, 200, 204


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Flash Memory

USB thumb drive

Laptop Batteries

Ni-CD; Ni-MH; Lithium

Keyboard Features

may not have dedicated numeric keypad

function key functionalities

Docking Options

Port replicator - replicates ports on laptop

maintains connections to physical devices

Docking Station

does what port replicator does

replicates the ports on a laptops

also contains slots for interface cards, hard disks

Inverter

provides backlight to the display

Diffuser

takes the points of light and uniformly spreads them around over the entire area of the

display

Backlight

Wi-Fi antenna

Printers 11%

Printer Basics


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Duplex Printing - printing on both sides of the paper

Duplex Assemblies - flips paper over, allowing printing on both sides

Bi-directional printing - printing from right-to-left and left-to-right

Print Resolution - dots per inch (dbi)

Printer Speed - Pages per minute (ppm)

Two main types of paper feeds

Continuous

one long sheet with lines to tear it into single sheets

feeder holes along the edges

Friction - single sheets of standard paper fed through the prinrter using pressure rollers

Laser Printers

Primary Corona - if there is no charge to it, all the toner would be applied to the entire drum

surface, resulting in a black page

Lazer - write on the drum

Used in businesses

Duplex Assembly - flips paper over front to back

Consumable - toner cartridges are replaceable/ recycle

Speed: 10-100 pages per minute; depending on model

Lowest cost per page

Quality: 600 DPI (Dots Per Inch)/1,200 DPI/ 2,400 DPI

Speed: ppm (Pages Per Minute) Imaging drum

fuser assembly

transfer belt

transfer roller

pickup rollers

separate pads

duplexing assembly

EP (Electrophotographic Process)

Processing

image processing engine receives the page, font, text and graphics from printer

driver

creates page image, then stores it in memory (RAM)

if there is not enough memory for page image, it is a page error


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Charging

conditioning

cylinder-shaped imaging drum receives negative charge - 600Vdc from

conditioning roller (old printers use corona wire)

corona wire - powered by power supply

full surface of drum is charged - it keeps charge only in darkness

Exposing

writing

mirror moves laser beam across surface of drum

Records image on drum by reducing charge to -100Vdc

(LED printer activates LED array to record image instead)

Developing

Toner is applied to drum by the developer

Toner has charge of -600Vdc

Attracted to -100Vdc areas/ repelling from the others because they have same

charge

Transferring

While sheet goes in printer, it receives a charge of +600Vdc by corona wire orroller

Positive charge attracts toner from negative drum

As paper moves, charge is cancelled by static eliminator strip, so it doesnt stick

Fusing

Fuser rollers pull sheet and heat toner onto paper at 350F

Cleaning

Leftover charge is removed by discharge lamp, turns to 0 Volts

Rubber blade removes excess toner on drum for reuse

Colored Laser Printing

4 Colors: Cyan, Magenta, Yellow, Black

Imaging drum is separate from toner

waste toner sent to waste toner container

transfer belt instead of imaging drum

Inkjet Printers

for small offices or home office (SOHO)

Connects through USB

uses ink cartridges filled with liquid ink for printing

separate cartridge for each color

aka CMYK device - Cyan, Magenta, Yellow, Black

Failed InkJets are often throwaway to replace, not repair


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Never turn off from Surge Protector - prevents printer from self-capping in cartridges

major cause for printer failures

problems with lines on paper is always because of the printhead

Paper pulled by rollers

High-Speed Mode- print head reverses direction at end of paper

Calibration - adjustments, printhead alignment

Thermal Inkjets

Bubble Inkjets

Heat is used to form bubble - thermal bubble

Bubble bursts onto paper

HP and Canon make most Thermal InkJets

Piezoelectric Inkjets

sprays colors from the cartridges onto the paper

printhead ejects small dots of color onto paper

ink sprayed on paper is stored in four separate cartridges monochrome printing - using black ink only

can print wide variety of media

applies current to the ink

Epson makes most of these

Thermal Printers

mostly used in stores for receipt

Thermal Head - generates heat, prints into paper

Platen - Rubber roller, feeds paper Spring - applies pressure to print head

Circuit Board - moves the print head

Direct Thermal - heat-sensitized paper

Thermal Transfer - glossy photograph paper

Direct Thermal Printing

Use heating element

Burns dots onto the surface of the special heat-sensitive paper - branding early fax machines used this method

uses special paper

Thermal Wax Transfer

heated print head moves over a colored wax ribbon

it melts the wax unto the underlying paper to create image, without touching it

doesnt use special paper


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Impact Printers

Force ink on paper

similar to typewriter

Daisy-Wheel - has wheel with pedals, each pedal has a letter

strikes against ribbon

can do duplicate, triplicate or higher forms

Carbon backing

Dot-Matrix

line printer

9, 18, 24 pins (NLQ)

Maintenance routine:

Replace the paper

Replace print head

Replace ribbon Clean print head

Vacuum paper and debris from printer

Print Device Sharing

Wired

USB

Parallel

Serial Ethernet

Wireless

Bluetooth

802.11x

Infrared (IR)

Printer Sharing

Maintenance

Follow proper printer cleaning instructions keep the paper path clean

clean the corona wire

vacuum up spilled toner

replace rollers as needed

Printers Driver Types


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PPD

PCL (Printer Command Language)

UPD (Universal Print Driver)

supports several types of printers

proprietary

Raster/bitmap

raster - area of the image being printed

bitmap - dot matrix representation of an image

Plotter/vector

plotter -

Driver must be compatible with the operating system

Drivers can be checked within Printer Properties

Drivers are available from three courses

installation discs

downloaded from the manufacturers website

Third party

Operational Procedures 11%

Six-Step Troubleshooting Process

Identify the problem

Establish a theory of probable cause

test the theory to determine cause Establish a plan of action to resolve the problem and implement the solution

verify full system functionality and if applicable implement preventative measures

document findings, actions and outcomes

ESD is most likely in cool, dry air

ESD is the cause of two objects that have dissimilar electric potential

Documents

Notes- CompTIA A+ (220-801).pdf