ROC I To II Glossary

Comprehensive vocabulary flashcards covering HFC architecture, DOCSIS 3.1 advancements, plant design symbols, signal leakage regulations, and troubleshooting methodologies.

Hybrid Fiber/Coax (HFC) Network

A broadband infrastructure that combines optical fiber and coaxial cable to deliver high-speed internet, streaming, and internet protocol (IP) video services.

Headend

A centralized facility where content is aggregated, processed, and modulated into RF signals before being transmitted over optical fiber.

Distribution Node

A component that performs optical-to-RF conversion, distributing signals over coaxial cables for last-mile delivery to end users.

Data Over Cable Service Interface Specification (DOCSIS)

The standard that manages bidirectional internet protocol (IP) traffic transfer between the customers' locations and the cable network.

Distributed Access Architecture (DAA)

An architectural shift that moves network functions from the central headend to remote fiber nodes at the edge of the network to enhance scalability and reduce costs.

Cable Modem Termination System (CMTS)

A gateway in the headend between the customer's cable modem and the internet, crucial for managing broadband services like internet and VoIP.

Loose-tube Fiber-optic Cable

A cable construction with multiple fibers loosely encased within a thermoplastic tube surrounded by water-resistant gel, ideal for harsh outdoor environments.

Armored Fiber-optic Cable

A cable featuring protective layers and armored tubing to shield against physical damage, suitable for direct burial and areas prone to rodent attacks.

Forward Path

The frequency range used for signals traveling from the service provider to the customer premises, typically typically from $54 \, \text{MHz}$ to $1 \, \text{GHz}$ in traditional systems.

Return Path (Return Band)

The frequency range for signals sending data from the customer premises back to the provider, typically $5 \, \text{MHz}$ to $42 \, \text{MHz}$ in traditional systems.

Full Duplex (FDX)

A technology that allows simultaneous upstream and downstream communication on the same frequency channel.

Extended Spectrum DOCSIS (ESD)

A pathway to extend the usable downstream spectrum up to $1.8 \, \text{GHz}$ while running upstream and downstream traffic on separate spectrums.

Fiber-to-the-x (FTTx)

A broad term for broadband network architecture using only optical fiber for all or part of the local loop used for last-mile telecommunications.

Laser Clipping

Distortion that arises when the laser in the optical transmitter is driven beyond its linear operating range, often caused by cumulative power from many channels.

Dense Wavelength-division Multiplexing (DWDM)

A technology that extends capacity by using multiple wavelengths (up to 40) on a single optical fiber to support long distances and scalability.

Remote PHY Device (RPD)

A device that relocates the Physical (PHY) layer functions closer to the customer, converting fiber data into RF signals.

Converged Interconnect Network (CIN)

The backbone that connects headends and data centers to the access network which directly services end users.

Low-Split (Sub-Split)

A return configuration where the upstream band covers frequencies from $5 \, \text{MHz}$ to $42 \, \text{MHz}$.

Mid-Split

A return configuration that expands the upper return frequency from $42 \, \text{MHz}$ to $85 \, \text{MHz}$.

High-Split

A configuration that extends the spectrum used for upstream data up to $204 \, \text{MHz}$ (or higher) to improve upload speeds.

Node Plus Zero (N+0)

A network topology where the coaxial cable portion operates without amplifiers between the fiber node and the customer.

Adjacent Channel Interference (ACI)

A type of self-interference occurring when energy from a transmitted upstream signal bleeds across the directional coupler and overloads the downstream receiver.

Plant Design

The strategic planning and layout of physical network components, including poles, cables, and amplifiers, represented visually on design maps.

Joint-use Pole

A power company-owned pole that allows attachments from other utilities such as telephone and cable companies.

Riser Pole

A pole that transitions electrical and utility cables between overhead (aerial) and underground systems.

Down Guy

An assembly anchoring the pole to the earth, comprising a thick galvanized steel cable diagonally anchored to the ground.

Vault

A below-grade housing that provides access to authorized individuals and protects critical broadband infrastructure from damage.

Quantum Reach (QR)

A specialized type of hardline coaxial cable known for its flexibility compared to standard P3 cables.

Tombstone (Data Block)

A reference point on an HFC plant map used for identifying and managing the technical performance of nodes, amplifiers, and line extenders.

Power Inserter

A device that injects electrical power into the coaxial cable while isolating the power from the data signal to maintain signal integrity.

Loop Resistance

The sum of the center conductor resistance and the shield resistance of a coaxial cable, typically specified in $\Omega \, \text{per} \, 1,000 \, \text{feet}$.

Ferroresonant Transformer

A transformer in a network power supply that provides a stable output voltage regardless of the amount of current drawn.

Time Division Multiple Access (TDMA)

A process that allocates specific time slots in a channel for multiple devices to transmit, preventing data collisions in a shared return path.

Funneling Effect

The progressive merging of upstream signals, unwanted noise, and ingress from everywhere in the network onto a common path toward the headend.

Long-loop Automatic Gain Control (AGC)

A process where signal level control begins at the headend and sends amplitude adjustments to modems or STBs to compensate for drop system attenuation.

Diplex Filter

A component in amplifiers and nodes containing a low-pass filter for the return path and a high-pass filter for the forward path.

Signal Leakage (Egress)

The emission of radio frequency signals from a cable system into the surrounding environment.

Ingress

Any undesired over-the-air signal or noise entering the cable system that interferes with the desired broadband signals.

Cumulative Leakage Index (CLI)

A figure of merit calculated annually to measure a cable system's compliance with FCC signal leakage regulations.

Air Distress Signal Frequency

A critical aeronautical frequency at $121.5 \, \text{MHz}$, which is close to the video carrier for analog cable Channel 14.

Emergency Aircraft Survival Signal Frequency

A critical aeronautical frequency at $243.0 \, \text{MHz}$, close to the video carrier of analog cable Channel 27.

LTE Leakage

Egress at frequencies above $700 \, \text{MHz}$ which can interfere with cellular telephone service and public safety systems.

Tagger

A device at the headend that modulates a low-frequency signal ($3 \, \text{Hz}$ to $25 \, \text{Hz}$) onto a carrier to produce a distinctive warble for leakage identification.

Metacognition

The process of thinking about how you think, involving awareness and control of your own cognitive processes.

Inductive Reasoning

Bottom-up logic where a reasoning process starts with evidence to support a probable conclusion.

Deductive Reasoning

Top-down logic where one moves from a general statement (premise) known to be true to apply it to a specific situation.

Orthogonal Frequency Division Multiplexing (OFDM)

A multicarrier transmission scheme used in DOCSIS 3.1 that uses many narrowband carriers modulated independently to increase spectral efficiency.

Low-density Parity-check (LDPC)

A robust and efficient forward error correction (FEC) coding scheme introduced in DOCSIS 3.1.

Metal Oxide Varistor (MOV)

An input surge protection device in a power supply that diverts surge voltage to ground before equipment is damaged.

Resolution Bandwidth (RBW)

A setting on a spectrum analyzer that determines how well it can distinguish and display close-together frequency signals.

Zero Span Mode

A spectrum analyzer setting where the sweep is stopped at a center frequency to display amplitude variations over time.

Optical Time-domain Reflectometer (OTDR)

A test instrument that sends light pulses down the fiber to measure length, attenuation, and points of reflection such as splices or breaks.

Precision Time Protocol (PTP)

A synchronization protocol used in DAA to maintain a delay of less than $1 \, \text{ms}$ between separated MAC and PHY layers.

Spine-Leaf Switching

A scalable network topology for DAA where every leaf switch connects to every spine switch to reduce bottlenecks and minimize latency.