BICSI RCDD Exam Dumps, RCDD Practice Test Questions

Answer: C. Electromagnetic Compatibility (EMC)

Explanation:

EMC (Electromagnetic Compatibility) refers to a device's ability to function properly in an environment with electromagnetic interference (EMI) without causing unacceptable interference to other devices.

EMI (Electromagnetic Interference) is the disturbance caused by external electromagnetic fields that can affect the performance of a device, but it doesn't describe the ability to tolerate it.

RFI (Radio Frequency Interference) is a specific type of EMI related to radio frequencies but is not the term that describes the device's ability to tolerate interference.

Fast Transients and ESD (Electrostatic Discharge) are types of interference or events that can cause damage to electronic devices but are not related to the device's overall electromagnetic compatibility.

Question 2:

Which of the following is NOT generally considered a source of electromagnetic interference (EMI)?

Answer Choices:

A. Copiers
B. Transformers
C. Incandescent Lights
D. Fluorescent Lights
E. Electrical Power Supply Cable

Answer: C. Incandescent Lights

Explanation:

Incandescent Lights typically do not generate significant electromagnetic interference (EMI). While they can cause some interference, it is much less than that produced by other devices listed here.

Copiers and Transformers are known sources of EMI, as they involve high-voltage electrical components that can emit electromagnetic fields.

Fluorescent Lights and Electrical Power Supply Cables are also common sources of EMI due to the electrical currents flowing through them, which can create electromagnetic disturbances.

Question 3

What type of optical fiber should be selected for a 10 Gb Ethernet connection over a 275-meter (902-foot) backbone between the equipment room (ER) and the telecommunications room (TR)?

A. OM1
B. 50 Micron Multimode
C. 50 Micron Laser-Optimized Multimode
D. 62.5 Micron Multimode

Answer: C

Explanation:
For a 10 Gb Ethernet connection over a 275-meter (902-foot) backbone, the key consideration is the fiber type that can support the required bandwidth and distance. Here’s the breakdown of the options:

OM1 fiber is an older type of multimode fiber with a core diameter of 62.5 microns. While OM1 can support speeds up to 1 Gb over short distances, it is not suitable for 10 Gb Ethernet connections over distances as long as 275 meters. OM1 is typically limited to around 33 meters for 10 Gb Ethernet, making it inadequate for this scenario.
50 Micron Multimode fiber (also called OM2) has a smaller core size compared to OM1 and provides better performance. However, its bandwidth is still insufficient to support 10 Gb speeds effectively over distances greater than 82 meters. Therefore, it also won’t support 10 Gb Ethernet over the required 275-meter distance.
50 Micron Laser-Optimized Multimode fiber (OM3 or OM4) is designed for higher speeds, such as 10 Gb Ethernet, and offers significantly better performance over longer distances than standard 50 Micron Multimode. Specifically, OM3 can support 10 Gb Ethernet up to 300 meters, which matches the distance requirement of 275 meters in this case. It is optimized for use with laser-based light sources, allowing for higher data rates and longer distances than standard multimode fiber.
62.5 Micron Multimode fiber (OM2 or OM1) has a larger core size and performs similarly to OM1 in terms of distance limitations for 10 Gb Ethernet. This fiber type is also not optimal for 10 Gb speeds over distances greater than 82 meters, which makes it unsuitable for the 275-meter requirement.

Therefore, the best choice for 10 Gb Ethernet over a 275-meter backbone is 50 Micron Laser-Optimized Multimode (OM3 or OM4), as it provides the required performance for this distance and speed.

Question 4

Which type of optical fiber is most commonly used for outdoor (OSP) fiber optic installations?

A. Tight-buffer
B. Loose-tube
C. Breakout Style
D. Duplex Zip Cord
E. Ribbon

Answer: B

Explanation:
When selecting optical fiber for outdoor (OSP) fiber optic installations, the key factor is the type of fiber cable that can withstand the environmental conditions commonly found in outdoor settings, such as exposure to moisture, temperature fluctuations, and physical stresses. Here’s the analysis of the options:

Tight-buffer fiber refers to a fiber with a protective coating that is directly applied to the fiber strand. While tight-buffered cables are durable and commonly used in indoor environments and shorter cable runs, they are less suitable for outdoor installations due to their vulnerability to environmental stressors like temperature and humidity. Tight-buffer cables are typically used in indoor applications or for short cable runs inside buildings.
Loose-tube fiber is the most common choice for outdoor (OSP) installations. It consists of fibers housed in loose tubes filled with a gel or water-blocking material to protect the fiber from moisture and temperature fluctuations. The design allows for the fiber to expand and contract with temperature changes without causing damage, making it ideal for outdoor environments. Loose-tube cables are rugged, flexible, and designed to withstand the harsh outdoor conditions, such as UV exposure, temperature extremes, and moisture.
Breakout Style fiber cables are typically used in indoor environments and involve individual fibers being separated within a larger cable. While this type of cable can be used in certain outdoor scenarios, it is not as common as loose-tube fiber in outdoor applications.
Duplex Zip Cord is primarily a patch cable configuration used in indoor applications, typically for data centers or office networks. While zip cord cables are easy to handle and deploy, they are not designed for outdoor installations due to their lack of weather protection.
Ribbon fiber cables consist of multiple fibers arranged in a flat structure. While they can be used for high-density applications, they are generally more suited for indoor environments or high-capacity installations within controlled environments. Ribbon cables are not typically the primary choice for outdoor installations due to their specific handling requirements and lack of outdoor protection.

Thus, the most suitable choice for outdoor (OSP) installations is loose-tube fiber, as it offers the best protection against environmental factors, making it the industry standard for outdoor fiber optic cables.

Question 5:

What is the standard insertion loss for a multimode mechanical splice?

A. 0.05 dB
B. 0.1 dB
C. 0.3 dB
D. 0.5 dB
E. 1.0 dB

Answer: C

Explanation:

The insertion loss of a multimode mechanical splice refers to the amount of signal loss that occurs when a fiber optic cable is spliced, specifically through mechanical means, such as with an alignment sleeve. In the context of multimode fiber optic splices, mechanical splicing is often chosen for its simplicity and cost-effectiveness compared to fusion splicing.

Insertion loss is a key parameter in evaluating the quality and performance of a fiber optic splice. Ideally, lower insertion loss means that less signal is lost during transmission through the splice. A typical insertion loss for multimode mechanical splices generally falls in the range of 0.1 dB to 0.5 dB, but 0.3 dB is widely recognized as a standard figure. This range accounts for potential variations in splice quality, such as the precision with which the fibers are aligned and the quality of the mechanical splice hardware itself.

Looking at the provided answer options, 0.3 dB (Choice C) is the most accurate reflection of the typical performance for a multimode mechanical splice. This value is based on both practical observations and manufacturer specifications for such splices, where a loss of around 0.3 dB is common. Although values as low as 0.1 dB (Choice B) might be achievable under optimal conditions, it is much less typical for real-world mechanical splicing scenarios, and losses as high as 1.0 dB (Choice E) would suggest an unusually poor splice.

Insertion loss is an important factor because excessive losses can degrade the overall performance of the fiber optic network, reducing the distance the signal can travel or requiring additional signal amplification. Therefore, a splice loss of around 0.3 dB is considered acceptable in many applications, balancing cost, performance, and ease of installation.

Question 6:

What is the ISO/IEC class rating for ANSI/TIA Category 5e cables according to international standards?

A. Class B
B. Class C
C. Class D
D. Class E
E. Class F

Answer: D

Explanation:

The ANSI/TIA Category 5e cables, commonly referred to as Cat 5e, are a type of twisted pair cable widely used in networking environments. They are designed to support data transmission speeds up to 1000 Mbps (1 Gbps) over distances of up to 100 meters, which makes them suitable for various applications like Ethernet and other network communication systems. These cables are often used for both voice and data communications and are particularly prevalent in the creation of local area networks (LANs).

The ISO/IEC classification system for cabling standards corresponds to different performance levels, with each class being designed to handle specific transmission requirements. The ISO/IEC Class rating system is crucial as it defines the minimum performance levels that cables must meet in terms of frequency, bandwidth, and transmission distance.

For ANSI/TIA Category 5e cables, the corresponding ISO/IEC Class rating is Class E. This rating indicates that Cat 5e cables are capable of supporting transmission frequencies up to 100 MHz, which is sufficient for the transmission speeds required for modern networking systems like Gigabit Ethernet (1 Gbps).

Each class has specific performance criteria:

Class D (Category 5e) is rated for frequencies up to 100 MHz.
Class E (Category 6 and Category 6a) is designed for frequencies up to 250 MHz.
Class F (Category 7) supports up to 600 MHz.

The fact that Cat 5e falls under Class E signifies that it meets the necessary transmission standards for the 100 MHz frequency range and the associated performance expectations for high-speed data transmission at Gigabit Ethernet speeds.

Thus, for this question, the correct ISO/IEC class rating for ANSI/TIA Category 5e cables is Class E, as indicated by option D. This aligns with international standards set by ISO/IEC 11801, which provides a framework for the design and performance of cabling systems used for telecommunications and data networking.

Question 7

If three buildings are approximately 400 meters apart and the requirement is for 10 Gig Ethernet, which type of fiber should be used for this application?

A. 8 - 9 Micron Singlemode
B. 50 Micron Multimode
C. 50 Micron Laser-Optimized Multimode
D. 62.5 Micron Multimode

Answer: A

Explanation:
For a 10 Gigabit Ethernet connection over a distance of 400 meters, the fiber type that should be used depends on the distance and the speed requirements of the connection. Here's a breakdown of the options:

8 - 9 Micron Singlemode fiber is designed for longer distances and higher speeds. Singlemode fiber has a very small core size (around 8 to 9 microns) and is optimized for long-distance transmissions because the light travels through the core in a single mode, minimizing signal loss. For 10 Gig Ethernet connections, singlemode fiber is ideal for distances beyond 300 meters, and it can easily support distances like 400 meters or even longer.
50 Micron Multimode fiber is commonly used for shorter distances and is typically effective up to 300 meters for 10 Gig Ethernet. While it can support 10 Gig speeds, it would not reliably handle the full 400-meter requirement without significant performance degradation. Multimode fiber is used in applications where the distance is shorter and the light modes cause some signal degradation.
50 Micron Laser-Optimized Multimode fiber (OM3 or OM4) is designed to support higher speeds over longer distances than standard multimode fiber. However, even laser-optimized multimode fibers like OM3 are typically effective for 10 Gig Ethernet only up to 300 meters. For a 400-meter run, multimode fiber would not be the ideal choice because it would struggle to maintain the performance needed for the full distance.
62.5 Micron Multimode fiber (OM1) is an older type of multimode fiber and has even worse performance over long distances compared to 50 Micron Multimode. It supports lower data rates and would not be suitable for 10 Gig Ethernet over a distance of 400 meters. This fiber is limited to shorter distances, typically up to 33 meters for 10 Gig speeds.

Therefore, for 10 Gig Ethernet over 400 meters, the best option is 8 - 9 Micron Singlemode fiber because it can easily support long-distance, high-speed connections with minimal signal loss.

Question 8

Which of the following is the correct procedure for bonding the drain wire and screen foil in screened twisted pair (STP) cable assemblies?

A. The drain wire and screen foil should be bonded at only one end.
B. The drain wire and screen foil must be bonded at every connection.
C. Bonding of the screen foil and drain wire is unnecessary.
D. The drain wire and screen foil should be bonded at opposite ends.

Answer: A

Explanation:
In screened twisted pair (STP) cable assemblies, the purpose of the screen foil and drain wire is to provide electromagnetic shielding to prevent electrical interference and signal degradation in the transmission line. Here's an explanation of the options:

The drain wire and screen foil should be bonded at only one end: This is the correct procedure for grounding in STP cables. The drain wire and screen foil are typically grounded at one end, often at the transmission equipment or network equipment end. Bonding at only one end helps to prevent the creation of ground loops, which can cause signal distortion and electrical noise in the cable. This approach ensures effective shielding without introducing potential safety hazards from ground loop currents.
The drain wire and screen foil must be bonded at every connection: This is not the correct approach. Bonding the drain wire and screen foil at every connection could lead to the formation of ground loops, causing interference and performance issues. Proper grounding at only one end ensures effective shielding without adding noise or unwanted signals.
Bonding of the screen foil and drain wire is unnecessary: This is incorrect. Bonding the drain wire and screen foil is essential to provide the required shielding and to protect the transmission line from electromagnetic interference (EMI). Without bonding, the cable would not function effectively in high-interference environments.
The drain wire and screen foil should be bonded at opposite ends: While grounding at one end is necessary, it is not typically done at opposite ends. Bonding at opposite ends could lead to ground loops, which can create more problems than they solve, such as voltage differences and signal interference.

Thus, the best practice is to bond the drain wire and screen foil at only one end to maintain effective shielding and prevent potential issues.

Question 9:

Which type of fiber optic connector is commonly used in high-speed data transmission applications, such as 10Gb Ethernet?

A. SC Connector
B. LC Connector
C. MTP/MPO Connector
D. ST Connector

Answer: C

Explanation:

When considering connectors used in high-speed data transmission applications, such as 10Gb Ethernet, it's important to evaluate their capabilities in terms of signal integrity, density, and overall performance. Among the fiber optic connectors commonly used for such applications, the MTP/MPO connector stands out due to its ability to support high-density, high-bandwidth applications.

The MTP/MPO connector is a multi-fiber connector designed for use in high-speed data environments. It is typically used in 10Gb Ethernet and even higher speeds like 40Gb Ethernet and 100Gb Ethernet, where the requirement for high fiber density is critical. The MTP/MPO connector can carry multiple fibers (up to 24 or more in a single connector), which makes it ideal for applications that require dense connections, such as data centers or large enterprise networks.

The MTP/MPO system is designed for parallel optics and high-density installations, making it a top choice for modern network infrastructures that need to support large data rates over short distances, such as within data center environments. This connector is able to meet the stringent requirements of high-speed networking, offering a better solution than traditional SC (A), LC (B), or ST (D) connectors.

While SC and LC connectors are widely used for single fiber applications in lower speed environments (like 1Gb Ethernet or legacy network systems), they do not offer the same level of fiber density and performance for the speeds required by 10Gb Ethernet. The LC connector is also popular for smaller form-factor setups but is generally used for fewer fibers and in lower-density environments compared to MTP/MPO connectors. Similarly, ST connectors are often used for older applications and not typically found in modern high-speed data environments like 10Gb Ethernet.

For these reasons, MTP/MPO connectors are the most commonly used connectors in high-speed data transmission applications, making C the correct choice.

Question 10:

In fiber optic cable installations, what does the term "attenuation" refer to?

A. The increase in signal strength over distance
B. The reduction in the quality of the signal as it travels through the fiber
C. The total bandwidth capacity of the fiber
D. The amount of light that is reflected back into the transmitter

Answer: B

Explanation:

In fiber optic systems, the term attenuation refers to the loss of signal strength as the light travels through the optical fiber. This phenomenon is critical to understand because attenuation impacts the quality and reach of the signal, which is central to the performance of fiber optic networks.

Attenuation is typically measured in decibels per kilometer (dB/km) and quantifies how much the signal weakens as it propagates along the length of the fiber. The key factors contributing to attenuation include scattering, absorption, and bending losses in the fiber. These losses occur because the light encounters imperfections or impurities in the fiber, which absorb or scatter the light. Over long distances, the accumulated attenuation can degrade the signal to the point where it is no longer usable, necessitating the use of repeaters or optical amplifiers to restore signal strength.

The term "attenuation" does not refer to an increase in signal strength (A) or the total bandwidth capacity (C) of the fiber. Rather, it specifically relates to the reduction in the quality of the signal (B) as it moves through the fiber. This reduction is significant in determining how far the signal can travel without degradation.

Additionally, attenuation is distinct from reflection or return loss, which refers to the amount of light that is reflected back toward the source (D). Reflection can occur due to poor splicing, improper connector alignment, or fiber end-face conditions, but it is a separate issue from attenuation. While reflection can also degrade signal quality, it is not the primary focus when discussing attenuation.

Therefore, the correct answer to this question is B, as attenuation directly describes the signal loss or weakening that occurs as the signal travels through the fiber. This loss limits the maximum transmission distance and influences the design and performance of fiber optic communication systems.