Which Kind of Cable Is Used in a Local Area Network? A Room-by-Room Guide to LAN Cabling

Every office network, from a five-person suite to a multi-floor headquarters, is built on a local area network. So which kind of cable is used in a local area network? The short answer is twisted pair Ethernet cable, usually Cat6 or Cat6A, for connecting devices, with fiber optic cable linking network closets, floors, and buildings.

The longer answer depends on where you are in the building. A LAN is not one cable but a system of connected parts, and each part has its own best cable. This guide walks through a LAN from the street to the desk, explains which cable belongs at each stage, and shows how LAN cabling evolved to where it is today. Businesses looking for reliable network cabling services in Carson, CA can get professional assistance with selecting, installing, and testing the right cabling for their network.

Table of contents

1. The short answer
2. What is a local area network?
3. How LAN cabling evolved
4. The six parts of a LAN cabling system
5. Which cable goes where: a quick map
6. Wireless LANs still run on cable
7. How to choose LAN cable for your building
8. Common mistakes and misconceptions
9. Future trends
10. Key takeaways
11. FAQ

The Short Answer: Which Cable Is Used in a LAN?

Most local area networks use two kinds of cable:

• Twisted pair Ethernet cable (Cat6 or Cat6A) runs from network switches to computers, phones, printers, Wi-Fi access points, and cameras.
• Fiber optic cable connects network closets to each other and to the main equipment room, especially between floors or buildings.

This matches how LANs are commonly described. Most wired network infrastructures utilize Category 5 or Category 6 twisted pair cabling with RJ45 compatible terminations. Depending on the grade of cable and quality of installation, speeds of up to 10 Mbit/s, 100 Mbit/s, 1 Gbit/s, or 10 Gbit/s are supported.

Coaxial cable, once the backbone of early LANs, now appears mainly where an internet provider’s service enters the building.

What Is a Local Area Network?

A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. That local management is what separates a LAN from a wide area network (WAN), which connects distant sites over carrier circuits or the internet.

LANs rely on two main technologies. Ethernet and Wi-Fi are the two most common technologies used for local area networks; historical network technologies include ARCNET, Token Ring, and LocalTalk. Ethernet runs over cable, while Wi-Fi runs over radio. As we will see, both depend on cabling.

Modern LANs are also built in a star layout. The most common LAN topology in use today is switched Ethernet, where each device has its own cable back to a switch. That star design is what makes structured cabling possible.

How LAN Cabling Evolved

The cable used in a local area network has changed dramatically since Ethernet was introduced.

The coaxial era (1980s)

The first commercial Ethernet ran on thick coax. 10BASE5 (also known as thick Ethernet or thicknet) is a version of Ethernet providing 10 Mbit/s bandwidth over a thick coaxial cable having a maximum length of 500 m (1,600 ft). It was the first commercially available version of Ethernet. Devices connected to one shared cable in a line, or bus.

Thicknet was difficult to install. The cable was so stiff that it earned nicknames, including one historical description as frozen yellow garden hose. A thinner coax followed. 10BASE2 uses thin coaxial cable terminated with BNC connectors to build a local area network, and it was the dominant 10 Mbit/s Ethernet standard during the mid to late 1980s.

The switch to twisted pair (1990 onward)

Twisted pair changed everything. By the early 1990s, 10BASE-T, defined in IEEE 802.3i in 1990, replaced the coaxial bus with a star topology using unshielded twisted pair (UTP) wiring, enabling hub-based connections up to 100 meters per segment. Faster standards followed on the same cable type. Coax was eventually retired for LAN use. In 2003, the IEEE 802.3 working group deprecated 10BASE5 for new installations.

Key point: The 100-meter limit that governs LAN cabling today traces back to the move to twisted pair star networks in 1990.

Today

Modern LANs use twisted pair for device connections and fiber for high-capacity links. The Ethernet standard now covers speeds from 1 Mbit/s to 800 Gbit/s, with twisted pair supporting up to 100 m (328 ft) and fiber reaching up to 100 km.

The Six Parts of a LAN Cabling System

In commercial buildings, LAN cabling follows the ANSI/TIA-568 structured cabling standard. The standard divides a building’s cabling into six parts, each with a defined job. The six components of structured cabling are the following: Entrance Facilities (EF). Equipment Room (ER). Backbone Cabling. Telecommunications Room (TR). Horizontal Cabling. Work Area (WA). Once the appropriate cable has been selected, learning how to wire a network cable can help explain the proper wiring and termination process for reliable network connections.

Here is which cable belongs in each one.

1. Entrance facility: where the outside world connects

The entrance facility is where internet, phone, and WAN circuits enter the building. It is the boundary between the carrier’s outside plant and your cabling.

Typical cable: Whatever the provider delivers, often fiber, sometimes coaxial cable for cable-based internet. Outside cable must transition to indoor-rated cable within a short distance of the building entry.

2. Equipment room: the heart of the LAN

The equipment room houses core switches, routers, firewalls, and servers. It is the central, climate-controlled space, often called the main distribution frame (MDF), that houses core servers, switches, and routers. It is the heart of the network where the backbone terminates.

Typical cable: Fiber and copper patch cords between equipment, plus terminations for backbone fiber arriving from each telecom room.

3. Backbone cabling: linking the rooms

Backbone cabling connects the equipment room to telecom rooms on each floor, and connects separate buildings on a campus. Backbone cabling connects Telecommunications Rooms (TRs) to the Equipment Room (ER), and connects separate buildings via Campus Backbone.

Typical cable: Fiber optic cable. Multimode fiber such as OM4 suits most in-building links, while single-mode fiber handles longer campus runs. One networking guide recommends upgrading backbone to OM4 or OS2 fiber for inter-floor and inter-building links.

4. Telecommunications room: the floor’s hub

Each floor or zone usually has a telecom room or network closet with patch panels and access switches. Telecommunications rooms or telecommunications enclosure connects between the backbone cabling and horizontal cabling.

Typical cable: Fiber arriving from the backbone, and copper twisted pair leaving for the horizontal runs.

5. Horizontal cabling: the runs to each outlet

Horizontal cabling runs from the telecom room patch panel to each wall jack, ceiling device, or floor box. Horizontal cabling connects the Telecommunications Room (TR) patch panel to the work area outlet (wall jack) on the same floor. It is the most numerous cable type in any building installation.

Typical cable: Solid-conductor twisted pair, usually Cat6 or Cat6A, with plenum or riser jackets as required. The permanent run is limited to 90 meters so the full channel, including patch cords, stays within 100 meters.

6. Work area: connecting the devices

The work area covers the short connection from the wall jack to the device. The standard describes it as covering from the telecommunication outlet to the station equipment, with components such as station equipment such as computers, data terminals, telephones, etc. Patch cables such as modular patch cords.

Typical cable: Stranded twisted pair patch cords with RJ45 plugs, usually factory-made for reliability.

Which Cable Goes Where: A Quick LAN Cabling Map

LAN subsystem	What it does	Typical cable
Entrance facility	Brings carrier services into the building	Carrier fiber or coax
Equipment room	Houses core switches, routers and servers	Fiber and copper patch cords
Backbone	Links equipment room, telecom rooms and buildings	Multimode or single-mode fiber
Telecommunications room	Connects backbone to horizontal runs	Fiber in, twisted pair out
Horizontal cabling	Runs from patch panel to each outlet	Solid Cat6 or Cat6A twisted pair
Work area	Connects outlet to device	Stranded Cat6 or Cat6A patch cord

For a small office with one network closet, the map is simpler. There may be no backbone at all, just a carrier connection, one rack, and twisted pair runs to every desk and device.

Wireless LANs Still Run on Cable

Wi-Fi is a LAN technology, but it does not eliminate cabling. Every Wi-Fi access point connects to the wired LAN through an Ethernet cable, which usually also powers it through Power over Ethernet. In a wireless LAN, users have unrestricted movement within the coverage area. The access points they connect to still sit on cable. Understanding what network cables are used for provides useful context for choosing the right cable for data transmission, device connections, and network communication.

Faster Wi-Fi has made that cable more important. TIA guidance specifically addresses access point cabling. TIA TSB-162-B, Telecommunications Cabling Guidelines for Wireless Access Points, recommends installing Cat 6A for horizontal cabling to WAPs. TSB-162-B also recommends using a grid-based zone cabling architecture, with at least two Cat 6A cable runs to each WAP in the grid.

Key point: A “wireless office” is really a wired network with radios at the edge. Planning Wi-Fi means planning cable.

How to Choose LAN Cable for Your Building

Use these steps to pick the right cable for each part of your local area network.

1. Map your spaces. Identify where carrier services enter, where core equipment will live, and whether you need one telecom room or several.
2. Count every connection. List workstations, phones, printers, access points, cameras, door readers, displays, and POS terminals. Plan spare outlets for growth. One structured cabling guide suggests a minimum 2 per work area (TIA-568); 4 per work area in high-density environments.
3. Pick horizontal cable by speed and power. Cat6 handles standard gigabit desk connections. Cat6A is the better choice for Wi-Fi access points, high-power PoE devices, and new construction meant to last.
4. Use fiber for backbone and distance. Connect telecom rooms, floors, and buildings with fiber. Choose multimode for in-building links and single-mode for longer runs or campus connections.
5. Keep horizontal runs within 90 meters. If a device is farther from the closet, add a telecom room or enclosure closer to it, or use fiber.
6. Match jacket ratings to the space. Use plenum-rated cable in air-handling ceilings and riser-rated cable between floors.
7. Plan for bonding and grounding. Racks, trays, and patch panels should be bonded per ANSI/TIA-607.
8. Require testing and documentation. Certify every link and label both ends so future moves and repairs are simple.

For more detail on cable categories, see our guides to [the most common type of network cable](INTERNAL LINK) and [the four types of cables](INTERNAL LINK). If you are planning a LAN in Carson, Long Beach, or the greater Los Angeles area, our [Network Cabling Company Carson CA](INTERNAL LINK) and [Commercial Network Cabling Company in Carson, CA](INTERNAL LINK) pages explain how we plan and install these systems.

Common Mistakes and Misconceptions

“Wi-Fi means we don’t need cabling.” Access points, and much of the equipment behind them, still depend on cable. Under-cabling for Wi-Fi is one of the most common planning mistakes.

Running copper between floors or buildings. Long backbone runs quickly exceed copper’s 100-meter limit. Fiber is the standard for backbone links, and it also avoids electrical issues between separate buildings.

Exceeding 90 meters on horizontal runs. Long runs may work at first but fail at higher speeds. Add a closer telecom room or switch location instead.

Using the cheapest cable available. Copper-clad aluminum and uncertified cable can cause speed problems and PoE failures. Use pure copper cable from reputable manufacturers.

Mixing cable categories in one channel. A Cat5e patch cord or jack on a Cat6A run limits the whole link to Cat5e performance.

Treating coax as LAN cable. Coax belongs at the carrier connection or in TV and legacy video systems, not in new data runs.

Skipping documentation. An unlabeled LAN turns every future move into a tracing job.

Future Trends in LAN Cabling

• Cat6A as the default horizontal cable. Faster Wi-Fi and higher PoE loads are pushing new projects toward Cat6A.
• Fiber closer to the edge. Some designs extend fiber to zone enclosures or even to desks in high-performance environments.
• More building systems on the LAN. Cameras, door access, lighting, and HVAC controls increasingly connect over Ethernet, which adds more drops per building.
• Multigigabit access. 2.5 and 5 Gbps switch ports let many existing Cat5e and Cat6 runs deliver more speed without recabling.
• Zone cabling. Grid-based layouts with consolidation points make it easier to add devices in open offices.

Key Takeaways

• Twisted pair Ethernet cable, usually Cat6 or Cat6A, is the main cable used in a local area network.
• Fiber optic cable links network closets, floors, and buildings in the LAN backbone.
• Coaxial cable powered early LANs but is now mostly limited to carrier service entry and video.
• LAN cabling follows ANSI/TIA-568’s six subsystems, and each part has its own best cable.
• Horizontal runs are limited to 90 meters, with a 100-meter total channel.
• Wireless LANs still depend on cabling, and TIA recommends Cat6A to access points.
• Good LAN cabling includes proper jacket ratings, bonding, testing, and documentation.

Frequently Asked Questions

Which kind of cable is used in a local area network?
Most local area networks use twisted pair Ethernet cable, typically Cat6 or Cat6A, to connect devices. Fiber optic cable is used for backbone links between network closets, floors, and buildings.

What is the most common LAN cable?
Unshielded twisted pair Ethernet cable with RJ45 connectors is the most common LAN cable. Cat6 is widely used in current installations, and Cat6A is increasingly specified for new commercial projects.

Is fiber used in a LAN?
Yes. Fiber is common in the LAN backbone, connecting the main equipment room to telecom rooms and linking buildings. Some high-performance networks also run fiber closer to devices.

Is coaxial cable used in LANs?
Not for modern LANs. Early Ethernet used coaxial cable, but twisted pair replaced it in the 1990s. Today coax mainly appears where cable internet service enters a building.

What is the maximum cable length in a LAN?
For twisted pair Ethernet, the standard limit is 100 meters per channel, made up of up to 90 meters of permanent cable plus patch cords. Fiber can run much farther.

Do wireless LANs need cabling?
Yes. Wi-Fi access points connect to the wired network through Ethernet cable, which usually also powers them. TIA guidance recommends Cat6A cable for access point connections.

What is the difference between LAN cable and Ethernet cable?
In everyday use, they mean the same thing. “LAN cable” usually refers to the twisted pair Ethernet cable that connects devices to a local area network.