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What are the 6 components of structured cabling?
The six components of structured cabling are Entrance Facilities, Equipment Room, Backbone Cabling, Telecommunications Room, Horizontal Cabling and Work Area.
Prior to the late 1970s, cabling for voice and data communications systems was less complex than it is today. As digital transmission grew, new types of wiring and connectors emerged.
In decades past, most systems used two-pair or four-pair copper wire sheathed in a binder to protect the cable. Connections involved stripping off the end of the wire to expose the copper conductor. This was then attached to a set of connectors, called a connecting block, which connected physical devices to a switching apparatus, such as a private branch exchange (PBX) system.
By the early 1980s, network engineers wanted to simplify connecting devices to their primary system. New wiring and connectors would hopefully speed up the process of building a wired infrastructure for both voice and data devices, and structured cabling has greatly simplified that process. Its continued use enables support for new equipment, such as IoT systems.
What is a structured cabling system?
Cabling, connectors and different wiring types -- including copper, fiber and coaxial -- needed more standardization as wiring and connection points evolved. In 1991, the American National Standards Institute and Telecommunications Industry Association set forth a series of standards known as ANSI/TIA-568.
The ANSI/TIA-568 standard introduced guidelines for all aspects of residential and commercial building cable distribution systems. Its sections included two designations:
- Generic Telecommunications Cabling for Customer Premises. This standard provides specifications for the structure, performance and other installation guidelines for generic cabling. Its current iteration is known as ANSI/TIA-568.0-E.
- Commercial Building Telecommunications Infrastructure Standard. This standard builds upon the standard for generic buildings and offers additional specifications for commercial building environments. Its current iteration is ANSI/TIA-568.1-E.
These standards shape the structured cabling system. Structured cabling has six components that, together, provide a convenient, repeatable and easily implemented framework for installing telecommunications cabling.
The six structured cabling subsystems
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).
1. Entrance Facilities
Cables that enter a building or residence from the outside -- such as a local service carrier or private network -- pass through an opening in the exterior wall through a conduit. The cable enters a room where other devices are deployed, such as the following:
- Network connection points.
- Patch panels.
- Equipment racks.
- Hardware connectors.
- Power supplies.
- Protection devices for grounding, shielding and lightning.
2. Equipment Room
The ER is the area where entrance cabling connects to the internal building wiring infrastructure. It houses patch panels that provide connections for backbone, horizontal and intermediate cabling. It also contains network switches, PBXs and servers. Network technicians should environmentally control the ER to maintain temperature and relative humidity levels based on equipment vendor specifications.
3. Backbone Cabling
Also called vertical cabling or riser cabling, backbone cabling links EF, telecommunications, other ERs and carrier spaces. It's typically installed on vertical channels, or risers, that connect to each floor. Backbone cabling has the following two subsystems:
- Cabling Subsystem 2. Cabling between a horizontal cross-connect and an intermediate cross-connect (IC).
- Cabling Subsystem 3. Cabling between an IC and the main cross-connect (MC).
Backbone cabling uses the following cable types:
- 100-ohm twisted-pair cabling, including Cat5, Cat6 or Cat7.
- Multimode optical fiber cabling. The recommended cable type is 850-nanometer laser-optimized 50/125-micrometer. However, 62.5/125 μm and 50/125 μm are also permitted.
- Single-mode optical fiber cabling.
Entrance cables are usually determined by the carrier and are not the user's responsibility.
4. Telecommunications Room
The TR is an environmentally controlled area that can be a dedicated room, known as a telecommunications enclosure, or part of another larger room, such as a general utility room. Hardware in these spaces terminates horizontal and backbone cables. The TR is also where network technicians use local cables, called jumpers or patch cords, on patch panels to cross-connect different cables. Network teams might also install ICs or MCs here to provide additional connection resources.
5. Horizontal Cabling
Horizontal cables deliver telecom resources to users' work areas or other rooms on the same floor. Typical cables run from the user's device to the nearest TR on the same floor. Regardless of cable type, the maximum allowed cable length between the TR and the user device is 295 feet.
Also known as Cabling Subsystem 1, horizontal cabling includes the cable, connectors, patch panels, jumpers and patch cords in the TR or TE. Multiuser telecommunications outlet assemblies and consolidation points connect multiple devices or cables to a single connector.
Horizontal cable types include the following:
- Four-pair 100-ohm unshielded or shielded twisted-pair cabling in Cat5e, Cat6 or Cat7.
- Multimode optical fiber cabling, two-fiber with a higher fiber count. The recommended cable type is 62.5/125-micron or 50/125-micron multimode cable.
- Single-mode optical fiber cabling, two-fiber with a higher fiber count.
6. Work Area
The WA is the final destination in a structured cable system. It is the area from a connector, or jack, in a wall outlet to a user device using a cable. Common user devices in the work area include PCs or mobile devices.
Why is structured cabling important?
Structured cabling simplifies cable infrastructure installation and supports a wide variety of voice and data communications equipment. Whether installing a coaxial outlet in a home or wiring a skyscraper, all components must meet specific standards for the following:
- Electrical transmission.
- Resistance.
- Cable lengths.
- Connectors.
- Cable fabrication.
Structured cabling also enhances troubleshooting for wiring problems when using the proper diagnostic equipment designed to be compatible with the ANSI/TIA-568.0/1 standards. Standardized interfaces also make structured cabling installation easier. Network technicians typically install these interfaces with snap-in connectors.
Structured cabling benefits
Structured cabling simplifies cable infrastructure installation, troubleshooting and maintenance of cable infrastructures. Network teams save money by standardizing all hardware components and cable types. Other benefits of structured cabling include the following:
- Scalability. Structured cabling enables easy installation, as connectors and their wiring simplify the connection process. This also makes infrastructure expansion and modification easy for any future growth.
- Flexibility. Structured cabling supports a wide range of devices and applications, so networks can integrate new technologies without fundamentally changing the network. The ANSI/TIA-568 standard is adaptable to virtually any kind of residential and commercial wiring requirements.
- Reliability. Because structured cabling follows industry standards and best practices, it ensures a reliable network. By following these practices, networks minimize signal loss, interference and downtime.
Paul Kirvan, FBCI, CISA, is an independent consultant and technical writer with more than 35 years of experience in business continuity, disaster recovery, resilience, cybersecurity, GRC, telecom and technical writing.
