RCDD Chapter 5 Backbone Distribution Systems

The statement suggests that vertically aligned TRs with connecting sleeves or slots are the most common type of backbone pathway. This means that when designing a backbone pathway, it is common to have TRs (Telecommunications Rooms) arranged vertically, with sleeves or slots connecting them. This arrangement allows for efficient and organized routing of cables and facilitates easy access for maintenance and troubleshooting. Therefore, the correct answer is true.

The statement is true because the location and configuration of slots in a structure can have a significant impact on its structural integrity. A structural engineer is trained to analyze and assess the design of a structure, including the placement and arrangement of slots, to ensure that it can safely support the loads it will be subjected to. By approving the location and configuration of slots, a structural engineer helps to ensure that the structure will be structurally sound and meet the necessary safety standards.

Singlemode optical fiber should be considered to support extended distances of high-speed applications because it has a smaller core size compared to multimode fiber, allowing for less dispersion and attenuation of the signal. This makes it more suitable for long-distance transmission of high-speed data.

The correct answer is "All the above" because all three methods mentioned - pigtail splicing, field connectorizing, and installation of preconnectorized assemblies - are commonly used to terminate optical fiber cables. Pigtail splicing involves splicing a pigtail cable to the main cable, field connectorizing involves connecting connectors directly to the main cable in the field, and installation of preconnectorized assemblies involves using pre-made assemblies with connectors already attached. All of these methods can be used depending on the specific requirements and circumstances of the fiber optic installation.

The statement is true because sleeves or slots should not block or obstruct the space where a wall terminates. This is important for proper installation and functioning of various components such as pipes, wires, or cables that may need to pass through the wall. By ensuring that the sleeves or slots do not obstruct the wall-terminating space, it allows for a clean and efficient installation process.

When choosing transmission media, it is important to consider multiple factors. The flexibility of the medium with respect to supported services is crucial as it determines the range of applications that can be supported. The required useful life of backbone cabling is also a significant factor as it ensures the longevity and durability of the network infrastructure. Additionally, the site size and user population need to be taken into account to determine the appropriate transmission media that can handle the required capacity. Therefore, considering all these factors is necessary for making an informed decision.

A TE, which stands for telecommunications equipment, is indeed a case or housing that is used to store and protect telecommunications equipment, cable terminations, and cross-connect cabling. This equipment is crucial for the functioning and organization of telecommunications networks. Therefore, the statement "A TE is a case or housing for telecommunications equipment, cable terminations, and cross-connect cabling" is true.

In multistory buildings, it is advisable to vertically align TRs whenever possible. This means that the TRs (Technical Rooms) should be arranged in a vertical alignment, preferably one on top of the other. This arrangement allows for efficient and organized management of the technical infrastructure of the building, such as electrical systems, HVAC (heating, ventilation, and air conditioning) units, and communication networks. By aligning the TRs vertically, it becomes easier to route cables and conduits between floors, minimizing the need for complex and lengthy installations. Additionally, this arrangement simplifies maintenance and troubleshooting processes, as technicians can easily access the necessary equipment and systems.

Improperly supported heavy cables can cause a variety of issues. Broken optical fibers can occur if the weight of the cable is not properly distributed and puts excessive pressure on the delicate fibers. Stretching of copper conductors can happen if the cable is not adequately supported, leading to potential damage and loss of signal quality. Slippage between the cable pairs and the sheath can also occur if the cable is not properly secured, leading to potential disconnection or signal interference. Therefore, all of the above options can be caused by heavy cables that are improperly supported.

The correct answer is OFCP. OFCP stands for Optical Fiber Cable Plenum, which indicates that the cable is suitable for installation in plenum spaces, which are areas in buildings used for air circulation. Plenum spaces require cables with fire-resistant and low-smoke properties to prevent the spread of fire and toxic fumes. OFCP cables meet these requirements and are commonly used in commercial buildings. OFNP, OFNR, OFCR, OFN, and OFNG are also fiber cable markings, but they do not specifically indicate suitability for plenum spaces.

The correct answer is OFNP. Nonconductive optical fiber plenum cable is marked as OFNP. Plenum cables are designed to be used in plenum spaces, which are areas in a building used for air circulation, such as the space above a drop ceiling or below a raised floor. OFNP cables have a nonconductive jacket that does not emit toxic fumes when exposed to fire, making them suitable for plenum spaces where fire safety regulations are strict. OFCP, OFNR, OFCR, OFN, and OFNG are other types of fiber cable markings, but they do not specifically indicate nonconductive plenum cables.

Placing backbone cable pathways in elevator shafts is not recommended. Elevator shafts are high-risk areas with constant movement and potential for damage to the cables. Additionally, the electromagnetic interference from the elevator machinery can negatively affect the performance of the cables. It is advisable to choose safer and more suitable locations for backbone cable pathways.

The correct answer is Category 3/Class C. Category 3 cables are capable of transmitting data at speeds up to 16 megahertz, which matches the specified frequency in the question. Class C refers to the performance level of the cable, indicating that it meets certain standards for signal quality and interference reduction. This makes Category 3/Class C the most suitable option for a multipair backbone balanced twisted-pair cable specified up to 16 megahertz.

The correct answer is Category 5e/Class D. This category and class of cable are specified to support frequencies up to 100 MHz. Category 5e cables are commonly used for Ethernet networks and can support data rates of up to 1000 Mbps. Class D refers to the performance level of the cable, indicating that it meets certain specifications for crosstalk and attenuation.

The correct answer is OFN, OFNG. OFN stands for Optical Fiber Nonconductive and OFNG stands for Optical Fiber Nonconductive General-purpose. These cable markings indicate that the optical fiber cable is nonconductive, meaning it does not conduct electricity. This is important for safety purposes, as it reduces the risk of electrical hazards when installing or using the cable.

The correct answer is OFC, OFCG. OFC stands for Optical Fiber Cable and OFCG stands for Optical Fiber Cable, General Purpose. These cable markings indicate that the cable is conductive, meaning it has a conductive layer or component that helps to dissipate static electricity and prevent damage to the fiber optic components. Conductive optical fiber cables are commonly used in environments where there is a risk of static electricity buildup, such as in industrial settings or areas with high electrical interference.

The correct answer is CMR. CMR stands for Communications Riser and is a marking used for balanced twisted-pair cables that are suitable for vertical runs in a building's riser shaft or between floors. It indicates that the cable has a higher fire resistance rating and is designed to prevent the spread of fire between floors.

The statement is true because the recommended optical multimode fiber cables have a graded-index optical fiber with a core/cladding diameter of either 62.5/125 um or 50/125 um. This means that the core of the fiber has a diameter of either 62.5 um or 50 um, while the cladding has a diameter of 125 um in both cases.

The correct answer is OFCR. OFCR stands for "Optical Fiber Cable Riser" and is a cable marking used for conductive optical fiber riser cables. This marking indicates that the cable is suitable for vertical runs between floors in a building. OFCR cables have fire-resistant properties and are designed to prevent the spread of fire from one floor to another.

The correct answer is CMX, LIMITED USE. This marking indicates that the cable is a balanced twisted-pair cable and is suitable for limited use in communications. The "CMX" marking signifies that the cable meets the requirements for general-purpose communications use, while the "LIMITED USE" designation indicates that it is not intended for long-distance or high-performance applications.

Steel armoring is necessary for rodent protection in any direct-buried optical fiber cable. Rodents can cause damage to the cable by chewing through it, which can lead to interruptions in the signal transmission. The steel armoring provides a physical barrier that protects the cable from rodent attacks, ensuring the reliability and durability of the cable in underground installations. Therefore, the statement is true.

The correct answer is .46 m sq (60 in sq)/4000m sq (40000 ft sq). This means that the size of the pathway using slots should be one slot sized at .46 m sq (60 in sq) for up to 4000m sq (40000 ft sq) of usable floor space served by that backbone system.

The correct answer is CMP. CMP stands for Communications Plenum Cable, which is a type of balanced twisted-pair cable used in plenum spaces, which are areas in a building used for air circulation. These cables have a special fire-resistant jacket that meets the safety requirements for plenum spaces. CMR, CM, CMG, CMX LIMITED USE, and CMUC are not the correct markings for communications plenum cable.

The correct answer for this question is CMUC. CMUC stands for "Communications Undercarpet Cable" and is used to mark balanced twisted-pair cables specifically designed for undercarpet installations. This marking ensures that the cable meets the necessary standards and is suitable for use in this specific application.

The choice of transmission media depends on several factors. One factor is the flexibility of the medium in terms of the services it can support. Different applications may require different types of transmission media. Another factor is the required useful life of the backbone cabling, as some transmission media may have a longer lifespan than others. Additionally, the size of the site and the number of users also play a role in determining the appropriate transmission media. Therefore, all of the factors mentioned above need to be considered when choosing the transmission media.

The statement is true because placing ties approximately 1 m apart with a minimum of three ties per floor is a common practice in construction. Ties are used to provide stability and prevent the walls from spreading or collapsing. By placing them at regular intervals, the load is evenly distributed, ensuring the structural integrity of the building.

Inserting cable ties (usually made of 1.25 mm (.049 in) steel) to secure the backbone cable through the layers of the strand before overall strand tensioning is a true statement. This process helps to ensure that the backbone cable remains securely in place and prevents any movement or slippage during tensioning. Cable ties are commonly used in various industries for bundling and securing cables, and in this case, they are used to provide additional support and stability to the backbone cable.

The maximum pullin tension of cables refers to the maximum force that can be exerted on the cables without causing damage or failure. If this tension exceeds the limit, it can lead to the cables being stretched, broken, or pulled out of their connectors. Therefore, the number of cables that can be installed in a condit may be limited by this maximum pullin tension to ensure the safety and integrity of the cables.

The correct answer is Singlemode. OS1 fiber classification refers to a type of optical fiber that is used for long-distance communication. It has a small core diameter, typically around 9 microns, which allows for the transmission of a single mode of light. This type of fiber is designed to minimize signal loss and is commonly used in telecommunications networks and high-speed data transmission applications.

All-dielectric cables are manufactured using fiberglass rods or aramid yarn. These cables do not contain any metallic elements, making them suitable for use in areas with high electrical interference or where grounding is not possible. They provide excellent insulation and are resistant to electromagnetic interference. All-dielectric cables are commonly used in outdoor installations, such as aerial or underground applications, where they offer high durability and protection against environmental factors.

Bridge and Taps are not usually permitted as part of the building backbone cabling. This is because bridge and taps are typically used in distribution cabling, which connects the building backbone cabling to individual work areas. The building backbone cabling, on the other hand, is responsible for connecting equipment rooms, telecommunications closets, and entrance facilities within a building. Therefore, bridge and taps are not typically allowed in the building backbone cabling.

This type of cable is called a loose-tube cable. It is designed for outdoor use and contains a water-blocking compound to provide water resistance. Additionally, it allows for some expansion and contraction with temperature changes.

If the desired end equipment is not equipped with the connector chosen for the cabling system, hybrid cords can be used to connect the end equipment to the patch panel. Hybrid cords are designed to have different connectors on each end, allowing for compatibility between different types of connectors.

A TR, or Telecommunications Room, is a designated space within a building that is used to house various telecommunications equipment, such as servers, routers, switches, and telephone systems. It is also used for cable terminations, which are the points where cables are connected or terminated, and for cross-connect cabling, which allows for the interconnection of different equipment within the TR. Generators and printers are not typically housed in a TR.

Multimode optical fiber is commonly used for campus or building applications because it allows for the use of cost-effective transceivers. This type of fiber can transmit multiple signals simultaneously, making it suitable for short-distance communication within a limited area such as a campus or building. Therefore, the statement that multimode optical fiber is not generally used for campus or building applications due to the inability to use cost-effective transceivers is incorrect.

Singlemode fiber cable has a zero-dispersion wavelength of 1310 nm. Zero-dispersion wavelength refers to the wavelength at which the fiber optic cable has the lowest dispersion, meaning that the different wavelengths of light travel at the same speed and arrive at the destination at the same time. This wavelength is important in long-distance communication as it helps to minimize signal distortion and ensure efficient transmission of data.

The correct answer is CM, CMG. CM and CMG are markings used for balanced twisted-pair cables in communication systems. CM stands for "communication" and CMG stands for "communication general." These markings indicate that the cables are suitable for general communication purposes and meet the necessary safety and performance standards.

Slots should have a minimum high curb of 25mm (1in) to ensure proper drainage and prevent water from pooling on the surface. A high curb helps to contain the water within the slot and directs it towards the drainage system, preventing any potential damage to the surrounding area. Additionally, a minimum high curb of 25mm (1in) provides stability and support to the slot, ensuring its durability and longevity.

The correct answer is 4000m sq (4000ft sq). The explanation for this answer is that for every 1000m sq (1000ft sq) of area, four sleeves or conduits are required. Therefore, for an area of 4000m sq (4000ft sq), four sleeves or conduits are needed, plus an additional sleeve or conduit.

OFNR stands for Optical Fiber Nonconductive Riser. This cable marking indicates that the cable is suitable for vertical installations in buildings, such as between floors, where fire regulations require a nonconductive cable. OFNR cables have fire-resistant jackets and are designed to limit the spread of fire and smoke.

Rack-mounted hardware is installed in standard 19 in or 23 in racks or cabinets. These dimensions refer to the width of the rack or cabinet, which is standardized in the IT industry. The 19 in measurement is commonly used for server racks and network equipment, while the 23 in measurement is often used for telecom equipment. The standardization allows for easy installation and compatibility between different hardware components.

In multiplexed transmission, multiplexing equipment in TRs and ERs combines signals from many end points for transmission over 2 strands of optical fiber. This means that multiple signals are being combined and transmitted simultaneously over only 2 strands of fiber, which allows for efficient use of the available bandwidth.

Indoor hardware refers to the equipment and devices used within buildings or enclosed spaces. This includes a wide range of items such as computers, printers, televisions, and kitchen appliances. On the other hand, outdoor hardware generally consists of items like outdoor lighting, security cameras, and garden tools. The statement suggests that the variety of indoor hardware is greater compared to outdoor hardware, implying that there are more options and types of indoor hardware available in the market.

Optical fiber is often the most cost-effective transmission medium for data systems because it offers several advantages. Firstly, optical fiber has a high bandwidth capacity, allowing for faster data transmission compared to other mediums. Additionally, it has low signal loss over long distances, making it suitable for long-haul transmissions. Optical fiber is also immune to electromagnetic interference, ensuring reliable data transmission. Furthermore, it is lightweight and compact, making it easy to install and maintain. Overall, these factors contribute to optical fiber being a cost-effective choice for data transmission.

The statement implies that as the usable floor space served by the backbone increases by 4000 m sq (40000 ft sq), the slot area should be increased by .46m sq (60ft sq). This indicates a positive correlation between the usable floor space and the required slot area. Therefore, the answer "True" suggests that increasing the usable floor space served by the backbone necessitates an increase in the slot area.

When the number of sleeves or the area of the pathway requires more than one row of sleeves, the designers should restrict the number of rows to two wherever practicable. This is because having more than two rows of sleeves can increase the complexity and cost of installation and maintenance. By limiting the number of rows to two, it allows for easier access and reduces the chances of congestion or interference between the sleeves.

A one-level hierarchical star campus backbone design would connect all the buildings to the Main Campus (MC) or Central Distribution (CD). This means that all the buildings would be directly linked to the main hub or central distribution point, allowing for efficient and centralized communication and data transfer within the campus network.

Nonconductive backbone optical fiber cables must be handled with care to avoid damaging the delicate fibers inside. The minimum bend radius refers to the smallest radius that the cable can be bent without causing signal loss or physical damage. When the cable is not under any load, it should have a minimum bend radius of 10 times its outside diameter. However, when the cable is being pulled, it is subjected to more stress, so the minimum bend radius increases to 15 times its outside diameter to prevent any damage to the fibers.

Optical fiber backbone cabling is commonly used for multiplexed transmission. Multiplexing is a technique that allows multiple signals to be combined and transmitted over a single fiber, increasing the efficiency and capacity of the network. This is achieved by dividing the fiber into multiple channels, each carrying a different signal. Therefore, the statement that the most common application for optical fiber backbone cabling is multiplexed transmission is true.

The two types of buffering mechanisms for optical fiber cable are tight buffered (indoors 900um) and loose tube (outdoors 250um). Tight buffered cables have a protective coating directly on the fiber, making them suitable for indoor use. Loose tube cables, on the other hand, have a gel-filled tube surrounding the fiber, providing protection against moisture and other environmental factors, making them suitable for outdoor use.