A transmission medium is a physical or logical pathway over which information or data travels. These mediums can be guided (where waves are guided along a physical path) or unguided (transmission and reception are achieved by means of antennas). Here are some common transmission mediums:
Guided (Wired) Media:
Twisted Pair Cables:
- Used for telephone lines and local area networks (LANs).
- Consist of pairs of copper wires twisted together.
- Examples: Category 5e (Cat5e), Category 6 (Cat6).
Coaxial Cables:
- Consist of a single copper conductor in the middle with multiple layers for insulation, shielding, and an outer conductor.
- Commonly used for cable television and internet.
Fiber Optic Cables:
- Transmit data as pulses of light through strands of glass or plastic.
- Capable of high-speed data transfer over long distances.
- Used for internet, telephone, and television services.
Waveguides:
- Metal tubes used to carry microwave signals.
Unguided (Wireless) Media:
Radio Waves:
- Cover a wide range of frequencies and are used in various applications like AM/FM radio, TV, and Wi-Fi.
Microwaves:
- Used for satellite communication and wireless broadband.
- Also used in microwave ovens (but that’s a different kind of application).
Infrared (IR):
- Commonly used in remote controls for TVs and other devices.
- Can also be used for short-range data transfer between devices.
Visible Light:
- Examples include Li-Fi technology where data is transmitted using visible light from LED lamps.
Ultraviolet (UV) Light:
- Less common in communication, more often used in other applications like sterilization.
Terrestrial Microwave:
- Earth-based transmitters and receivers communicate with each other, often placed on top of mountains or tall structures to clear obstacles.
Satellite Microwave:
- Uses satellites to relay the signal around the world.
Each transmission medium has its own advantages and disadvantages in terms of bandwidth, speed, propagation delay, cost, and ease of installation and maintenance. The choice of a particular medium depends on the specific requirements of the communication system, such as distance, budget, and data transmission rate.
Key terms in plain language
Open a term for a concise explanation of language used on this page.
Broadband
A general term for always-on, high-speed Internet access. Broadband can be delivered over fiber, cable, DSL, fixed wireless, cellular, or satellite networks.
Fiber Internet
Internet delivered through strands of glass using light. Fiber commonly supports high capacity, low latency, and strong upload performance, but availability must be confirmed for the exact address.
Bandwidth
The amount of data a connection can carry in a given time, usually measured in Mbps or Gbps. More bandwidth supports more users, devices, and simultaneous applications.
Latency
The time it takes data to travel between two points. Lower latency improves voice, video meetings, cloud applications, gaming, and other real-time services.
Dedicated Internet Access (DIA)
A business-grade Internet connection with capacity dedicated to the customer rather than shared in the same way as typical consumer broadband. It often includes symmetrical speeds and an SLA.
SD-WAN
Software-defined wide area networking. It manages multiple connections and chooses paths based on application needs, performance, and policy to improve resilience and control.