knowledge

Overview

Network media and connections define the physical and wireless methods used to transmit data between devices. The three primary categories are copper cabling, fiber optic, and wireless — each with different standards, speeds, interference characteristics, and use cases.


Terminology

TermDefinition
EthernetWired networking standard using twisted pair or coaxial cabling (IEEE 802.3)
WiFiWireless networking standard (IEEE 802.11)
EMI (Electromagnetic Interference)Electrical noise that disrupts signal transmission
RF InterferenceRadio frequency noise that disrupts wireless or copper signals
UTP (Unshielded Twisted Pair)Basic twisted pair cable with no additional shielding
STP (Shielded Twisted Pair)Twisted pair cable with foil shielding to reduce interference
Straight-Through CableTwisted pair cable wired the same at both ends; connects different device types
Crossover CableTwisted pair cable with swapped wiring at one end; connects similar device types
WAP (Wireless Access Point)Device that provides wireless network access via antenna
SSID (Service Set Identifier)Name used to identify a wireless network; devices must match to connect

Core Concepts

Copper Cabling

Uses electrical signals to pass data between devices.

Coaxial Cable

  • Nearly obsolete for new LAN installations
  • Still used for cable TV and residential internet
  • Reduces induction, EMI, and RF interference

Twisted Pair Cabling

Multiple copper cables twisted into pairs to reduce interference.

TypeDescriptionCommon Use
UTP (Unshielded Twisted Pair)Basic twisted pair; no additional shieldingHome and office environments
STP (Shielded Twisted Pair)Foil shield for additional interference reductionModern infrastructure, static environments

Cable Wiring Standards

TypeWiringConnects
Straight-ThroughSame pin order at both endsDifferent device types (e.g., PC to switch)
CrossoverPins swapped at one endSimilar device types (e.g., PC to PC)

Fiber Optic

Transmits pulses of light rather than electrical signals through glass or plastic fiber.

  • High bandwidth and high speed
  • Communicates across long distances without signal degradation
  • Immune to EMI and RF interference
  • Part of the IEEE 802.3 Ethernet standard family

Wireless Networking

Wireless transmission uses radio frequency (RF) signals to carry data through the air without physical cabling.

Wireless TypeDescriptionRange / Use
Radio WavesMost common; travels through walls and obstaclesWi-Fi, Bluetooth, cellular
Infrared (IR)Line-of-sight only; does not pass through wallsTV remotes, older IrDA devices
MicrowavesHigh-frequency; used for point-to-point linksSatellite, cellular backhaul

Wi-Fi (IEEE 802.11)

  • WAP (Wireless Access Point) — antenna-based device that provides wireless connectivity to endpoint devices
  • SSID (Service Set Identifier) — name that identifies a wireless network; all wireless devices must share the same SSID to communicate

Cellular Networks

Mobile devices connect to cell towers rather than WAPs. Different generations of cellular technology define the frequency bands and capabilities available.

GenerationKey Characteristics
3GIntroduced mobile data; enabled basic internet access on phones
4G / LTEHigh-speed data; enables streaming and VoIP
5GUltra-low latency; high throughput; supports IoT at scale
  • Cell towers use different frequencies for coverage range vs. throughput — lower frequencies travel farther but carry less data
  • Cellular networks present greater security risks than wired connections due to the broadcast nature of RF transmission


References / Images

  • IEEE 802.3 and 802.11 standards documentation
  • Copper vs fiber comparison diagrams