Network transmission media are mainly classified into two categories: twisted-pair cable and fiber optic cable. They differ significantly in transmission speed, distance, and interference resistance.

Twisted-Pair Cable:

Twisted-pair cable consists of eight copper wires twisted together in pairs. It is divided into unshielded twisted-pair (UTP) and shielded twisted-pair (STP).

UTP (Unshielded Twisted-Pair): No metal shielding layer, low price, weak interference resistance, suitable for ordinary office or home environments.

STP (Shielded Twisted-Pair): With a metal shielding layer, strong interference resistance, suitable for industrial or high electromagnetic interference environments.

Common Categories and Speeds:

Cat5 (Category 5): Supports 100 Mbps, suitable for 100 Mbps networks.

Cat5e (Category 5e): Suitable for 100 Mbps, mainstream choice for home and office use.

Cat6 (Category 6): Suitable for 1 Gbps (within 55 meters), stronger interference resistance.

Cat7 (Category 7): Suitable for 10 Gbps (within 100 meters), fully shielded design. |

Wire Sequence Standards:

T568A: White-Green, Green, White-Orange, Blue, White-Blue, Orange, White-Brown, Brown.

T568B: White-Orange, Orange, White-Green, Blue, White-Blue, Green, White-Brown, Brown. Straight-through cables (both ends are the same standard) are used to connect different devices. Crossover cables (one end T568A, one end T568B) are used for direct connection of similar devices.

Transmission Principle: Twisted-pair cables reduce electromagnetic interference by twisting the wires together. Pins 1 and 2 are used for transmitting data, and pins 3 and 6 are used for receiving data.

Fiber Optic Cables: Fiber optic cables use glass or plastic fibers as the transmission medium to transmit data through optical signals. They are divided into single-mode and multimode.

Single-Mode Fiber (SMF):

Features: Small core diameter (9μm), allows only a single optical mode of transmission, long transmission distance (up to 70 km or more), high data rate (100 Gbps+).

Applications: Long-distance communication, such as metropolitan area networks (MANs) and backbone networks.

Multimode Fiber (MMF)

Features: Large core diameter (50/62.5μm), allows for multiple optical modes of transmission, short distance (typically ≤2 km), low cost.

Applications: Short-distance high-speed transmission, such as data centers and enterprise intranets.

Common Interface Types:

FC type fiber optic interface: Metal threaded fixing, high stability, mostly used in telecommunications equipment.

ST type fiber optic interface: Clip-on fixing, commonly used in early networks.

SC type fiber optic interface: Square plug-in type, widely used.

LC type fiber optic interface: Miniaturized design, preferred for high-density connection scenarios.

Switches：Switches are core network devices used to connect multiple devices and forward data.

Functions

Efficiently forward data frames within a Local Area Network (LAN).

Learn device location through a MAC address table, reducing broadcast storms.

Types and Features

Unmanaged switches: Plug and play, no configuration function, suitable for small networks.

Managed switches: Support advanced functions such as VLAN and QoS, require command line or web interface configuration.

PoE Switch: Powers devices such as IP phones and cameras (e.g., 802.3af/at standard).

Layer 3 Switch: Features routing capabilities, suitable for large enterprise networks.

Configuration Methods

1.Connection Method: Connect to the switch management interface via a console cable or Ethernet cable.

2.Configuration Tools:

Command Line Interface (CLI): Use terminal software such as PuTTY, XShell, or SecureCRT.

Web Interface: Log in to the switch using a browser and enter its IP address.

3.Basic Configuration: Configure IP address, VLAN, port speed, etc.

Summary

Twisted Pair Cable: Economical choice for short distances, available in UTP/STP versions, with speeds ranging from 100 Mbps to 10 Gbps.

Fiber Optic Cable: High-speed transmission over long distances; single-mode is suitable for long distances, while multimode is suitable for short distances.

Switch: Select unmanaged/managed models as needed; configuration is completed via CLI or Web.