COMPTIA A+ 1101 Cards

What does SATA stand for?

Serial advanced technology connection

What does PCI stand for?

Peripheral component interconnect, legacy

Type of communication of PCI?

32bit and 64bit parallel communication

Voltage of PCI?

3.3V and 5V

What is the NFC range?

4cm

What does LCD stand for and how does it work?

Liquid crystal display, light shines through liquid filters

What are the types of LCD and what do they stand for?

TN = twisted nemantic

IPS = in plane switching

VA = vertical alignment

Difference between different LCD types?

TN = better response time, bad wide angles, low power

IPS = better colors, more expensive, good angles

VA = best contrast, bad angles

Different types of LCD backlights?

CCFL = cold cathode fluorescent lamp

LED

What is special about CCFL?

Uses AC power when the computer requires DC, so need an inverter

How many pins is USB-C? What makes it special?

24pins, can be used to transmit other signals (HDMI, DisplayPort)

What was used before USB connectivity and with what kind of signal? How many pins?

DB-9 cable with RS232 signal, 9pin

What kind of stylus' are there?

Capacitive stylus = touch pen

Active stylus = apple pencil, can communicate independently of the screen

What is the older type of headset connection? With what type of signal?

3.5mm TRRS (tip ring ring sleeve) with an analog signal

What were the 2G networks? What did they stand for?

GSM = global system for mobile communication

CDMA = code division multiple access

What companies used GSM and how did it work?

AT+T and T-Mobile, has multiplexing

What does multiplexing mean?

Multiple data signals use the same channel without interference

What companies used CDMA? How did it work?

Verizon and Sprint, each person used a different code

What was the purpose of 4G? What did it stand for?

To combine GSM and CDMA, LTE = long term evolution

What does EDGE stand for?

Enhanced data rates for GSM evolution

What is PRL? How does it update?

Preferred roaming list, so your cell phone can connect to the right tower, updates OTA (over the air)

How does GPS work?

30 satellites in the air, your device needs to see 4 for accurate location

What does MDM stand for? And do?

Mobile device management, companies can manage user devices through one console

What is meant by a partition?

Keeping company data and private data separate

What are the two types of IP payloads? What do they stand for?

TCP = transmission control protocol

UDP = user datagram protocol

What does in the clear mean?

Not encrypted

Why not just have the IP payload?

TCP and UDP allow for multiplexing with different applications and ports

How does TCP work?

Requires formal setup/teardown process to establish protocol, called a reliable system because will make sure data reaches server, also has flow control to make sure one side is not getting data too quickly

Examples of TCP?

HTTPS = hypertext transfer protocol secure

SSH = secure shell

How does UDP work?

No formal setup process, no confirmation of data sent, for real time communication

Examples of UDP?

DHCP = dynamic host config protocol

TFTP = trivial file transfer protocol

What are the different kinds of ports?

Non-ephemeral (permanent port) = same port for the same service

Ephemeral = client side port that changes

What is a key fact about ports? About TCP and UDP using ports?

For communication, not security

TCP and UDP can use the same port numbers at the same time

FTP?

File transfer protocol tcp/20 tcp/21 file transfer between systems

Telnet?

tcp/23 in the clear remote command console access

SSH?

Secure shell tcp/22 encrypted communication for command console

SMTP?

Simple mail transfer protocol tcp/25 only sending mail not receiving

DNS?

Domain name system udp/53 converts web addresses to IPs and vice versa

DHCP?

Dynamic host configuration protocol udp/67/68 assigns IP address settings to local machines

HTTP/HTTPS?

Hypertext transfer protocol (secured) tcp/80 tcp/443

POP3?

Post office protocol v3 tcp/110 mail just on one device

IMAP?

Internet message access protocol v4 tcp/143 manage email from multiple clients

SMB?

Server message block tcp/445 Windows file sharing and printer sharing

What is another name for SMB?

CIFS = common internet file system

NetBIOS?

Network basic input output system udp/137 tcp/139 is not used anymore

SNMP?

Simple network management protocol

Queries udp/161

Traps udp/162

What are queries and traps?

Queries = seeing how the network is functioning over time

Traps = Alerts with problems or changes

What are the different SNMP versions?

v1 = 1 query at a time in the clear

v2 = bulk transfers in the clear

v3 = message integrity added, auth, encryption

LDAP?

Lightweight directory access protocol tcp/389 Store and retrieve info in network directory

RDP?

Remote desktop protocol tcp/3389 Share desktop for remote location

What are common devices on a SOHO?

Wireless router, switch, firewall

What does a router do?

Routes traffic between different IP subnets

What type of connections can connect to a router?

LAN, WLAN, copper, fiber

What does a switch do?

Sends info based on MAC address, is the core of an enterprise network

ASIC?

Application specific integrated circuit, piece of hardware designed for a specific function Ex: digital voice recorder

What is an unmanaged switch?

Switch with no config options, no management protocols, just plug in and play

What is a managed switch?

VLAN support, traffic priority options, redundancy support, port mirroring and protocol analyzing, external management (SNMP)

What is VLAN?

Virtual Local Area Network, can divide different LANs

STP? (protocol)

Spanning Tree Protocol, prevents loops in a LAN

How does port mirroring work?

Network monitoring, mirror a port and send packets through the mirror to see what is going on

How does a patch panel work logistically?

Connect everyone on the floor to a patch panel (permanent connection), have this panel connect with RJ45 connectors than you can change easily

RJ45 connector?

Ethernet connector

How does proxying internet traffic work?

Have an intermediary server that scans for malicious data from the internet before coming back to the client

What are some traits of a proxy server?

Access control, caching, URL filtering

PoE?

Power over ethernet, data and power in one cable

Types of power sources for PoE?

Endspan = power comes from the switch

Midspan = in-line power that is injected between the device and the switch

PoEaf 2003?

15.4W DC, 350mA max current

PoE+at 2009?

225W DC, 600mA

PoEbt 2018?

Type 3 = 51W 600mA

Type 4 = 71.3W 960mA

What is a hub? Communication?

Before switches, data goes into one port and is sent to all other ports, half-duplex

What does duplex mean?

Data can be sent in both directions at the same time

What is a cable modem?

Copper cable connection for TV and internet, broadband connection, allows for the transmission of different data types across multiple frequencies

DOCSIS?

Data over cable service interface specification

DSL? How does it work and distance?

Digital subscriber line, telephone wire for internet, speed gets worse the farther away you get from the central office

ADSL?

Asymmetric digital subscriber line, because the download speed is greater than the upload speed

ONT?

Optical network terminal, fiber cable connects to box outside location to convert it to copper

What is a demarcation point? Another name for it?

Also called demarc, when the public network becomes your network

NIC?

Network interface card

SDN?

Software defined networking, taking switches, routers, etc. and making them software

What are three layers of devices?

Infrastructure layer = data plane of that device (forwarding, encrypting)

Control layer = the brain (routing table, session table)

Application layer/management = manage device using an API

What does NAT mean?

Network address translation

What does API mean?

Application programming interface

What does the difference in frequency mean for a wireless network in terms of range?

Higher frequency = more objects in the way will absorb therefore less range

Lower frequency = objects will bounce the signal therefore more range

What is the problem with 2.4GHz frequency?

Lots of other devices use this frequency (baby monitor, phones, bluetooth)

802.11a?

1999, 5Ghz freq, 54Mbits/s

802.11b?

2.4GHz, 11Mbits/s

802.11g?

2003, 2.4GHz, 54Mbits/s, backwards compatible with A and B

802.11n?

2009, WiFi4, 5GHz or 2.4GHz, 40MHz channel widths with 4 antennas, 600Mbits/s, MIMO

What is MIMO?

Multiple input multiple output

802.11ac?

WiFi5, 2014, 5GHz, 160MHz channels, eight MU-MIMO, 7GB/s

802.11ax?

WiFi6, 2021, 5GHz or 2.4GHz, many different channel widths, 1201Mbits/channel, 8 bidirectional MU-MIMO, OFDMA

What is OFDMA?

Orthogonal frequency division multiple access, works like cellular to improve high density situations

What is long range fixed wireless, and what is it called with a directional antenna?

2 buildings connected with 802.11 with an antenna, called a point to point connection

RFID? How does it work?

Radio frequency identification, using radar technology, radio energy powers a chip and therefore antenna

NFC? What are the traits of NFC?

Near field communication, mobile device can have a 2 way conversation with another device, short range with encryption support

How do channels work with 802.11?

Groups of frequencies are used with non-overlapping usage being ideal

Traits about bluetooth?

Uses 2.4GHz band, the unlicensed ISM band

What does ISM stand for?

Industrial scientific medical

What does the DNS do? Who runs it?

Converts web address names to IP addresses and vice versa, usually managed by ISP or IT enterprise

What is the DHCP and where is it located?

Automatic IP config and is on most home routers