Wireless Protocols Flashcards
Understand and evaluate (13 cards)
Front
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What are the main wireless frequency bands?
Industrial, Scientific, and Medical (ISM) band
Unlicensed National Information Infrastructure (UNII) band.
- 2.4 GHz: Used for Wi-Fi, Bluetooth, medical devices, cordless phones
- 5 GHz: Less crowded, faster speeds, supports channel bonding
(2.4 GHz = busy street, 5 GHz = faster highway with more lanes)
What are the channels in the 2.4 GHz band and how do they overlap?
There are 13 total channels (11 in North America).
Only channels 1, 6, and 11 don’t overlap.
(Overlapping = people yelling over each other. 1, 6, 11 = quiet turns.)
What are the channels in the 5 GHz band?
5 GHz has 23 non-overlapping channels and allows channel bonding for even higher speeds.
(It’s like a giant freeway with 23 clear lanes vs. a narrow street with traffic.)
What are the IEEE 802.11 Wi-Fi standards and how do they compare?
IEEE Standard | Wi-Fi Name | Frequency | Max Speed
802.11a | — | 5 GHz | 54 Mbps
802.11b | — | 2.4 GHz | 11 Mbps
802.11g | — | 2.4 GHz | 54 Mbps
802.11n | Wi-Fi 4 | 2.4/5 GHz | 600 Mbps
802.11ac | Wi-Fi 5 | 5 GHz | 1.3 Gbps
802.11ax | Wi-Fi 6 | 2.4/5 GHz | 9.6 Gbps
(Each version is like a new car model — faster, more efficient, better capacity.)
What is Bluetooth and what does it do?
Bluetooth is a short-range wireless protocol using 2.4 GHz, with a typical range of ~10 meters.
Used for headphones, keyboards, mice, game controllers, etc.
(Think of it like a digital handshake across a small table.)
What are the main Bluetooth versions and how do they differ?
- 1.1: 1 Mbps
- 2.0 + EDR: 3 Mbps
- 3.0 + HS: 24 Mbps (uses Wi-Fi burst)
- 4.0 + LE: Low power, designed for IoT
- 5.0: Better range, bandwidth, and stability
(Like phone generations: every version adds speed, efficiency, and smarter features.)
What is Near Field Communication (NFC) and how does it work?
NFC is a very short-range wireless protocol (0–2 cm) that uses 13.56 MHz.
Used for contactless payments, badge scanning, and asset tracking.
(Like tapping your ID on a door scanner — quick and up close.)
What is Radio-Frequency Identification (RFID)?
RFID uses electromagnetic fields to identify and track data on tags.
Tags can be powered (active) or unpowered (passive).
Components:
- Tag: Stores the data (like a box with information inside)
- Reader: Retrieves the data (like a key that unlocks the box)
- Antenna: Transfers the signal (like the hallway the key travels through)
(Think of RFID like unlocking a treasure chest remotely — tag = chest, reader = key, antenna = magical rope between them.)
What’s the difference between powered and unpowered RFID tags?
- Powered (active): Battery-powered, long range (~100m)
- Unpowered (passive): Draws power from reader, short range
(Active = flashlight, Passive = glow stick that needs UV light.)
What is long-range fixed wireless?
Wireless tech that delivers internet across long distances using directional antennas.
- Uses both licensed and unlicensed bands
- Range: ~160 feet up to several kilometers
(Like a digital zipline between buildings — long, direct, and efficient.)
What is the difference between Bluetooth, NFC, and RFID?
- Bluetooth: Two-way, short range (~10m), uses 2.4 GHz
- NFC: Two-way, very short range (0–2 cm), 13.56 MHz
- RFID: One-way (tag to reader), variable range (passive or active)
(Bluetooth = handshake, NFC = tap, RFID = barcode scan)
How do protocols and frequencies work together in wireless networking?
- Protocols define the rules
- Frequencies define the “channel” they communicate on
Examples:
- Wi-Fi protocols like 802.11ac use 5 GHz
- Bluetooth and some Wi-Fi use 2.4 GHz
(Protocols = language, frequencies = radio stations)
