The modern home consists of telephones, computers, televisions, and many other electronic devices. All of these devices require a structured cabling system to provide incomming services such as broadband Internet, cable or satellite, and telephone. In this article, we look at the TIA-570 standard for residential structured cabling and its subsystems.
What is Structured Cabling?
Structured Cabling Components
- Coaxial Cable
- A transmission line in which a central conductor is located within a cylindrical outer conductor, separated by insulation.
- Structured Cabling
- A communications cabling infrastructure within a building that consists of a number of standardized smaller elements called subsystems.
- TIA
- Telecommunications Industries Association — TIA is accredited by the American National Standards Institute (ANSI) to develop voluntary industry standards for a wide variety of telecommunications products.
- UTP
- Unshielded twisted pair cable.
- HTDV
- High Definition Digital Television — digital television format that provides high-quality widescreen pictures with compact disc-quality surround sound.
- NID
- Network Interface Device — A demarcation point between the exterior and interior of the residence.
- ADO
- Auxiliary Disconnect Outlet — Allows incoming services to be quickly disconnected for the purpose of testing.
- DD
- Distribution Device — Brings together outlet cabling and equipment cabling.
- TO
- Telecommunications Outlet — Provides the interface between the structured cabling system and the consumer equipment
- HDMI
- High-definition media interface — A compact audio/video connector interface used to transmit uncompressed digital streams. equipment
Structured Cabling is a communications cabling infrastructure that consists of a number of smaller elements called subsystems. The current standard for residential structured cabling is the TIA 570–B, released in April of 2004.
The TIA publishes the TIA 570–B Residential Telecommunications Infrastructure Standard, which addresses residential structured cabling systems, using coaxial cable and UTP cables. The TIA 570–B standard also includes information on security, whole–house audio and home automation cabling. There is an update to this standard that is currently being worked on that will provide additional performance requirements for the coaxial cabling to both accommodate current as well as future requirements, including HDTV and streaming video.
Figure 1 shows the subsystems of a structured cabling system.
Figure 1. A Structured Cabling System and its subsystems
- Network Interface Device (NID)
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The NID marks the demarcation point between the exterior and interior of the residence. This is typically the point at which the service provider has responsibility for exterior cabling up to the NID, and the electronic systems integrator has responsibility for the interior cabling beyond the NID.
- Auxiliary Disconnect Outlet (ADO)
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The NID is connected to the ADO, typically with one cable for each incoming service, such as telephone, cable television, satellite, etc. The ADO allows the incoming services to be quickly disconnected for the purpose of testing.
- Distribution Device (DD)
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The DD is connected to the ADO via a quick disconnect cable, known as the DD cable. The DD is the heart of the structured cabling system. It brings together outlet cabling and equipment cabling. When possible, the DD is centrally located in the residence, thus minimizing cabling lengths. In addition, it is placed in a location that provides a high degree of serviceability.
- Telecommunications Outlet (TO)
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The telecommunications outlets connect to the DD via TO cabling. The TO cables are typically UTP, coaxial, and occasionally fiber optic, when specifically recommended by the manufacturer for a specific purpose, like HDMI. (Currently fiber optic cable is generally replacing copper wire cable outside the home, and is rarely used inside the home unless specifically receommended by a manufacturer.) The telecommunications outlet provides the interface between the structured cabling system and the consumer equipment, such as telephones, televisions, and computers.
Commerical Vs. Residential
- Backbone cable
- Cable between multiple distribution devices (telecommunication panels).
- Main cross–connects
- Patch cords connecting the backbone cabling to a distribution device (telecommunications panel).
- Horizontal cross–connects
- Patch cords connecting horizontal cabling used to mechanically terminate to a distribution device (telecommunications panel).
- Horizontal cable
- Cable between the distribution device (telecommunications panel) and the telecommunications outlet (TO).
In many respects, a residential structured cabling system is a scaled–down version of a commercial structured cabling system. Table 1 provides a comparison of the terminology difference between residential and commercial structured cabling systems. The residential standard is covered by TIA/570–B, and the commerical standard is covered by TIA/568–C
| Residential | Commercial | |
| Service disconnect | ADO | N/A |
| Connection between cross–connect panels | N/A | Backbone cable |
| Cross–connects | DD | Main cross–connects, Horizontal cross–connects |
| Cable to TO | TO cable | Horizontal cable |
| User interface to system | TO | TO |
Table 1. Residential versus Commercial Cabling Systems
Best Practice: When installing backbone cabling, it is best to use a separate color for each type of backbone cable and to use plastic ties to separate the backbone cabling from other cables at the DD. In a home, very few types of backbone cables are used. Typically, backbone cables are used to connect the DD to the ADO and to other DDs. The TO cabling within a home, Figure 2, shows the best practice of using a separate color (blue) and ties for the cable entering the DD in a clean and organized fashion.
Figure 2. TO cable as it enters the DD
Grades of Cabling
- fiber optic cable
- A type of cable with a glass center core surrounded by a jacket made of layers of various forms of plastic that transmits data using light rather electricity.
- F connector
- A coaxial RF connector commonly used for terrestrial television, cable television, and satellite television.
- category 5e
- An extended version of category 5, which meets the TIA 568A–5 specification.
- category 6
- A twisted pair cable standard providing performance of up to 250 MHz, and meets the TIA 568B–2.1 specification.
- CATV
- Cable television also known as community antenna television or community access television..
- RJ45
- RJ45 is an 8P8C (8 position, 8 conductor) type of registered jack. It can be both male and female.
- T568AThe pin/pair assignments for eight–conductor 100–ohm balanced twisted–pair cabling with the orange pair at pins 3/6.
The TIA 570–B standard specifies two levels of cabling for each location. A location can consist of a single outlet, or a single room. It is permissible to break apart the cabling within a room or space to provide separate outlets. For example, the 4–pair UTP cable can be separated from the 75–ohm coaxial cable to create separate television and telephone outlets.
The two grades can be described as:
- Grade 1
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Grade 1 — Provides a generic cabling system that meets the minimum requirements for basic telecommunications services, such as telephone, satellite, CATV, and data services. A grade 1 outlet, shown in Figure 3, includes a single UTP cable rated at category 5e or better terminated with a RJ45 connector to the T568A standard. In addition, a single 75-ohm coaxial cable is included and terminated with an F connector. Occasionally, a fiber optic cable may be provided.
Figure 3. Grade 1 Cabling Requirements
- Grade 2
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Grade 2. Provides a generic cabling system that meets the minimum requirements for basic and advanced telecommunications services, such as high–speed Internet and in–home generated video. This grade provides for both current and developing telecommunications services. A grade 2 outlet, shown in Figure 4, includes two (2) UTP cables rated at category 5e or better terminated with an RJ45 connector to the T568A standard. In addition, two (2) 75-ohm coaxial cables are provided and terminated with F connectors. Occasionally, two (2) fiber optic cables may be provided.
Figure 4. Grade 2 Cabling Requirements
The standard also recommends the use of category 6 cable when possible rather than the category 5e. As for the coaxial cable, the commonly accepted industry best practice for 75–ohm coaxial cable is RG6 quad–shielded. Fiber optic cables are available in several options.
