Coaxial cable, often referred to simply as “coax,” has been a foundational element of cable television infrastructure for decades. With the rise of the internet, cable providers expanded their services to offer broadband internet access over these same coaxial cables. Here’s a detailed overview of coaxial cable and its use in cable internet:

Coaxial Cable Basics:

  1. Structure: A coaxial cable consists of a central copper conductor surrounded by an insulating layer, which is then shielded by a metal foil or braided shield. An outer insulating layer protects the entire assembly.
  2. Function: The design of coax helps to prevent external interference, ensuring a clean signal transmission.

Cable Internet:

  1. Data Transmission: Cable internet uses a modulation scheme to send data over the coaxial cables. The technology allows for both internet data and cable TV signals to coexist on the same line without interference.
  2. DOCSIS: Stands for “Data Over Cable Service Interface Specification.” It’s a telecommunications standard used to provide internet access via a cable modem. Successive versions of DOCSIS (e.g., DOCSIS 3.0, DOCSIS 3.1) have provided increasing speeds and efficiency.

Advantages of Cable Internet:

  1. Speed: Cable internet typically offers faster speeds than DSL.
  2. Consistent Connection: Speeds are generally consistent due to the physical connection, although they might decrease during peak usage times if many users in the same area access the service simultaneously.
  3. Ubiquity: As many homes already have coaxial cables for cable TV, it’s often easy to add internet service.


  1. Shared Bandwidth: Unlike DSL, where each user has a dedicated line to the central office, cable internet bandwidth is often shared among multiple households in an area. This means during peak times, users might experience slower speeds.
  2. Less Potential for Ultra-High Speeds: While cable can offer fast speeds, it doesn’t quite match the potential of fiber-optic connections, which can deliver gigabit speeds.

Cable Modems:

  1. Function: The cable modem is the device that connects a user’s home network to the internet via the cable provider. It modulates and demodulates digital signals to be sent over the coaxial cables.
  2. Router Combination: Many modern cable modems also incorporate Wi-Fi routers, allowing users to connect multiple devices wirelessly within their homes.

The Future:
Cable internet continues to evolve with advancements in DOCSIS technology, pushing the speed limits of what’s possible over coaxial cables. However, as fiber-optic networks continue to expand, they pose strong competition due to their higher speed capabilities and potential for future growth. Still, the vast existing infrastructure of coaxial cables ensures that cable internet will remain relevant for many years to come, serving areas where fiber deployment may not yet be feasible.