Cable Network Overview

What are the basic components of coax (from the inside out)?

(1) the center conductor; (2) dielectric; (3) solid aluminum sheath or outer conductor; (4) armor (if used); (5) jacket (if used); and (6) messenger (if used).

What are the three steps in the "Stop, Look, and Listen" method?

1) stops what he is doing and focuses his attention on what the customer is saying; (2) looks at the situation from the customer's perspective; and (3) listens to the customer completely with empathy and understanding.

What is needed to receive digital TV from any service provider?

A consumer needs a digital TV set or a digital set-top boxconnected to an analog TV set to receive digital TV from any service provider. For high definition TV, the consumer must purchase an HDTV set.

What is "makeready"?

A preconstruction procedure to ensure that there is sufficient clearance from existing utilities and that other regulations are complied with.

What are the six methods in which signals arrive at a cable system?

A. Over-the-air B. Terrestrial microwave C. Direct cable feed D. Satellites E. Locally produced F. Public switched telephone network

The signals used in broadband cable networks are part of the greater electromagnetic spectrum. What signals are included in the electromagnetic spectrum?

A. Radio frequencies (RF) B. Television C. Microwave D. Infared E. Visible Light F. X-rays G. Gamma rays H. Cosmic rays

What are POP measurements?

As required by the FCC, broadband cable operators perform proof-of-performance measurements each year. these measurements are used to verify that video, audio, and data signals at the headend and test points throughout the system meet FCC requirements.

What makes 3G devices unable to run on a 4G LTE network?

Because 4G LTE is based on different technology and runs on its own network, 3G devices are incompatible and cannot be run on 4G networks. Most 4G devices, however, are backward-compatible and will run over the 3G network.

How is cable placed in an aerial plant?

Before fiber or coax is placed in an aerial plant, steel support strand is strung, suspended, and attached to a clamp. The strand hangs at least 40 inches below utility power lines and 12 inches above telephone cables. It is then attached to the strand with steel lashing wire.

CMTS

Cable Modem Termination System

What is C/N?

Carrier-to-noise ratio is the ratio between the RF signal level to that of the noise level.

What is CSO?

Composite second order is the sum and difference of two signals at certain points above and below a video carrier frequency.

What is CTB?

Composite triple beat is the sum and/or difference of three video carrier frequencies.

What is X-mod?

Cross-modulation is the modulation of one signal by another.

What two departments work together to ensure bills are accurately and efficiently sent to customers?

Customer service and data processing

Which cable system department is typically responsible for maintaining communication with field personnel (i.e., installers and service technicians) and the customer service department?

DISPATCH

DMM

Digital Multimeter

DBS

Direct Broadcast Satellite

What is the distributed configuration?

Each power supply feeds cable & active devices to a separate section of the network.

On the upstream path, what happens to RF signals at the node?

F signals enter the node and are converted into light. A return laser sends the light signal to the headend.

What is the reason for the difference in the passband signal between the two network architectures?

Fiber can carry a much greater bandwidth over light frequencies before signals degrade beyond tolerable limits than can coax over radio frequencies.

How do fixed wireless and fixed optical networks operate?

Fixed wireless and fixed optical data networks operate much like the phone company, but without direct wire or fiber linkage. In most cases, a radio transmitter is based at the CO; there also is a connection to the Internet, through which a customer links to an Internet service provider.

HFC

Hybrid-Fiber-Coax

How is unity gain maintained in amplifiers?

If loss in the coaxial cable is different from the amplifier's gain, input attenuators and equalizers adjust the loss so that the gain remains the same and the signal level at the amplifier output is equal across the network.

What procedures does the technician follow in direct buried cable?

If the company's policies allow it, the installer can bury the cable with a shovel or hand-bury tool. Sometimes a contractor will be on hand to dig the path using a cable plow.

What does the downstream cable signal enter after leaving the bridger amplifier in a tree-and-branch design?

In a tree-and-branch design, the cable signal in the downstream path leaves the trunk at the bridger amplifier. There, it makes a transition to the feeder's domain. The signal is split and routed to as many as four output ports connected to separate (coax) feeder cables.

IP

Internet Protocol

ISP

Internet service provider (ISP).

What are several uses of status monitoring equipment?

It can indicate which amplifiers need level readjustments and record intermittent problems not present during normal working hours. Status monitoring equipment also can predict failures before they occur by monitoring such levels as battery capacity in a standby power supply.

MTA

MultimediaTerminal Adapter

What is digital signal?

No individual components and all picture components have been converted to ones and zeroes.

What are common passive devices used throughout the fiber-optic trunk?

Optical connectors, splitters, and splices

What usually is done after amplifiers are balanced?

Periodic sweeping of frequency response usually is done

Why is it important not to tie the drop cable to the body, belt, or D-ring when climbing a pole or extension ladder?

Personal injury or death can occur if a passing car or pedestrian pulls the cable while the installer is connected to it.

PSTN

Public Switched Telephone Network

Qos

Quality of Service

What are several types of passive devices?

RF line splitters, directional couplers, multitaps, line equalizers, power inserters, and the cable itself.

Why are sweeping, balancing, and POP compliance important?

Regularly performed sweeping and balancing help maintain compliance with FCC requirements. POP compliance also ensures quality service and excellent customer satisfaction. Some franchise authorities may require periodic reports of system technical performance as well.

What method does the installer follow when faced with a customer's concerns?

Stop, Look, and Listen" method.

How do customers benefit from the Digital Act of 2005?

The customer experience is enhanced by sharper images, better sound, more channels, and technologies such as HDTV and 3D TV.

How does the passband signal differ between the two network architectures in the downstream path?

The feeder in a traditional tree-and-branch design, where all the cable in both the trunk and feeder is coax and several amplifiers must boost the signal throughout the network, usually supplies a downstream passband signal of up to 50-550 MHz. In contrast, the feeder in an HFC network typically transmits the downstream signal in a 50-750 MHz, 50-860 MHz, or even 50-1,000 MHz (1 GHz) passband.

What kind of drop cable is used in underground installs?

The installer always uses nonmessengered, flooded drop cable except for the interior of the premises (where leaking compound could damage the customer's furniture, carpet, or CPE).

What is the technician's primary test measurement device?

The signal level meter (SLM)

What is centralized power configuration?

Uses several UPSs grouped in one location, sharing a common backup power system.

What do many states offer to provide this information?

a "one call" service that helps crews find exactly where all underground plant is located.

What do passive devices add to the signal?

add a factor called insertion loss to the signals (the attenuation between the input and output ports of the devices), which is a reduction in signal power and voltage.

What is a signal leakage detector?

an RF receiver with an antenna that can measure signals leaking (egressing) from the system within aeronautical frequency bands. The detector also can determine sources of signals leaking (ingressing) into the cable.

What equipment is needed for all installs?

an assortment of bonding hardware, and cable attachment devices are needed; traps and bandpass filters also may be necessary.

why do supporters often point to the Telecommunications Act of 1996 as a benefit to the public?

as a great benefit to the public: new companies could offer telecommunications services, and established providers could join forces by merging their businesses and network capabilities, which meant more choice, better service, and competitive pricing for end users.

Through what equipment does a signal pass in the downstream path in the tree-and -branch architecture?

begins at the headend and is transmitted through trunk coax and amplifiers. Several trunk cable runs each contain a number of amplifiers spliced into the cables. Line splitters and directional couplers route some of the signal onto additional trunk runs.

Where are traffic cones placed around the truck?

behind the left rear corner and by the left front of the truck. This ensures that other drivers on the road will be aware of hazards that might occur nearby (such as a child running into traffic in front of the truck to chase a ball in the street).

What is the role of amplifiers?

boost the power of a signal, which has lost some of its strength while traveling through the trunk cables and other passive devices.

What are three main types of amplifiers in the feeder?

bridger, distribution, and line extender

How are minimum drop clearances specified?

by company policy as well as local electrical codes, the National Electrical Code (NEC), and the National Electrical Safety Code (NESC).

What determines the drop cable route in an aerial installation?

by existing utility lines, the premises contact point, and the strand attachment point.

What determines the location of the exterior entry hole?

by the position of the TV set, existing utility boxes, the interior routing — and the desires of the customer.

What can happen by starting work without knowing this information?

can create utility service outages to hundreds and even thousands of homes and businesses. In addition, trenching into electric lines can electrocute a worker, breaching a gas line can cause a deadly explosion, and breaking the water line might flood a neighborhood and cut water supply.

What can happen if the wrong connector is installed?

can have negative consequences in the reliability of the network and signal quality at the customer premises equipment (CPE).

What must be done if the vehicle restricts the flow of traffic?

channeling devices such as cones are placed with proper tapering distances as specified by the U.S. Department of Transportation's Manual on Uniform Traffic Control Devices.

What are the two predominant types of network architectures?

coaxial cable tree-and-branch and hybrid fiber/coax (HFC).

What is the analog signal?

composed of three parts: video, color, and audio and are converted to a specific channel frequency for transport through the cable network.

What does a trunk station contain?

contains several modules and a power pack inside a metal weatherproof housing. Collectively, the housing and RF electronics are called a trunk station. The housing also features attenuation pads, equalizers, slope and gain controls, and diplex filters. Inside some amplifiers is a separate bridger amplifier that forms the transition point between the trunk and feeder.

What factors can affect attenuation?

decreases when the size of the coax increases. The attenuation increases when the cable must pass signals at higher frequencies. Temperature also can affect signal loss; for example, a 10°F rise in surrounding temperature causes a 1% rise in a cable span's attenuation compared to the cable's standard loss value.

What does the required number of test points depend on?

depends on the number of customers, the amount of bandwidth, and the number of channels in the system.

What determines the location of the span clamp?

depends on the pole's location relative to the premises, routing restrictions, the required minimum horizontal climbing space, and existing span clamps.

What is an express feeder?

designs use an express feeder cable, often the size of a trunk coaxial cable, as the signal path from the optical node's RF amplifier.

What did early cable systems distribute; what led to wireless video service?

distributors of local TV broadcasts over community antenna systems, to areas where customers could not reliably receive signals with a home antenna. Wireless video service developed because it took longer for cable service to arrive in some suburbs and apartment complexes. Seizing the opportunity, local businesses offered residents "wireless cable." The companies arranged with programmers to carry their channels over microwave frequencies granted by the FCC.

How do HFC networks divide the broadband cable operator's coverage area?

divides the broadband cable operator's coverage area into small "serving areas" of 150 to 2,500 customers. Each serving area contains an optical node connected to the headend or remote hub site by its own dedicated fiber cable.

To operate, what do active devices require?

electrical power

Why are UPSs used in optical networks and for lifeline telephony and high-speed data services?

eliminate the time delay between a loss of or a decrease in the utility power and the start-up of the battery-supplied inverter.

EMTA

embedded multimedia terminal adaptor

What are the functions of the sheath?

encloses the signals and prevents ingress and egress. It also provides structural support, return (ground) for AC current, and a constant impedance (total opposition to flow of electrical current) across the entire length of the coax.

Where does the express feeder end?

ends at the first distribution amplifier, where the feeder cable begins its journey to distribution taps.

What must crews ensure in aerial construction of optical plant?

ensure that the cable is not stressed beyond the manufacturer's recommended specifications. Pressures beyond this limit can result in microcracks and eventual cable failure.

What does a line extender amplifier do?

extends the feeder line somewhat farther into the service area.

What is the idea behind the express cable approach?

extends the reach of a particular optical node farther into the feeder system.

FTTF

fiber-to-the-feeder

How is the DMM used?

for checking the voltage and wiring polarity in an AC wall plate before connecting equipment at the customer premises. In the feeder, it can verify system and amplifier power supply operation.

What is WiMax?

has a much larger range from an outdoor transmitter.

How is the RF signal converted and transmitted in an HFC architecture?

he RF signal is converted into light at the headend. The light is transmitted by laser over fibers until reaching optical receivers in the nodes. The light signal is then converted back into RF, amplified and sent through the coaxial feeder to the drop.

What procedures does the installer follow once he has approached the strand attachment point and before touching the strand?

he always visually inspects the strand and cable, looking in both directions for downed secondary and/or primary power lines, electrical crews, or hazard tags. Using a voltage detector, he checks for the presence of AC voltage on unjacketed cables and on the strand prior to touching any of them.

HDTV

high definition TV

What does isolation identify?

identifies the level of signal interference possible between any two individual ports at a specific frequency, with all other ports terminated. Isolation prevents undesired RF signals from one output port from interfering with desired signals on another output port. The higher the isolation value, the better the isolation between the ports.

What are several power supply performance checks?

includes AC input and output voltage, output current, individual battery voltages, charging voltage, and standby switching capability.

How does expanded basic differ from basic services?

includes a number of additional nonpremium, satellite-delivered channels for a separate monthly fee.

What problems can cause a power failure within the cable network?

includes a tripped utility breaker in a power supply, spent standby batteries, a blown feeder leg fuse, a blown DC power supply fuse in an amplifier, and a coax center conductor suckout (when the center conductor pulls away from its connector due to extreme‑cold temperatures, poor workmanship, or undue physical stress).

Where must the installer be when drilling the entry hole through wood?

inside the premises

ingress

interfering over-the-air signals

How do directional couplers and splitters differ?

just like an RF splitter's, except that the signals that pass through each of the two output ports are not equal amounts.

What test equipment measures signal levels inside and outside the premises?

leakage detector, voltage detector, signal level meter, digital multimeter, and a continuity tester.

What do grounding and bonding prevent?

lightning-induced current or power surges — caused by faulty electrical wiring and equipment as well as direct contact between coax and high-voltage lines — from striking the drop cable and damaging CPE or injuring the customers or personnel.

How is digital voice service made available?

made available by connecting a multimedia terminal adaptor (MTA) to the cable modem or more often with an embedded multimedia terminal adaptor (EMTA) that integrates the cable modem and MTA in a single device.

What protects underground cable?

manufactured with protective jackets and flooding compounds.

What does the DMM measure?

measures AC and DC voltages, resistance, and current.

Describe the function of a TDR.

measures the presence of and distance to cable faults. It sends out a test signal and measures any reflections caused by impedance mismatches in the cable that are characteristic of cable faults.

What must the installer know before any digging begins?

must know where all underground electric, gas, water, and power lines are by performing the utility-location step.

How do many states help prevent incidents of cut or damaged underground cable?

offer a "one call" phone number service that helps crews find exactly where all underground plant is located.

What must be removed from the tap before attaching the F-connector?

often a locking terminator must be removed from the tap.

What is the result of an overbuild?

often a service similar to that of the broadband cable operator, with a complete array of digital offerings.

Where must the installer be when drilling the entry hole throughslate, stucco, brick & asphalt siding?

outside the premises

Depending on local regulations, how are fiber-optic and coaxial cables buried?

placed into the ground about 2 to 3 feet deep. Usually, a trench is made in the soil with motorized equipment.

What two aerial methods are common to bring cable into the plant?

pull-in: cable reel remains stationary and a construction worker in a bucket truck pulls the cable along drive-off: moving reel of cable attached to a truck is driven slowly underneath the strand while feeding the cable to the lasher.

What is a streaming video box?

pulls content from the Internet and/or networked mobile devices and displays it over an HD-enabled TV set.

Why are expansion loops used?

season-to-season temperature extremes (heat waves in the summer and hard freezes in the winter), the coaxial cable can expand and contract.

How do direct broadcast satellite operators transmit signals?

sends programming via satellite to a small dish antenna (about 18 inches across) at the customer premises. Reception requires an unobstructed line of sight from the satellite to the dish antenna. Often, the antenna is placed on the roof or the patio. A coaxial cable feeds the signal to an indoor satellite receiver, which decodes the signal for viewing on the TV set.

STB

set-top box

Why are amplifier levels balanced?

should be balanced at least twice a year to make sure they remain at design-specified output levels.

What is insertion loss?

signal loss between the tap's input port and its output port. The more customer tap ports a tap has, the higher its insertion loss.

egress

signals leaking out

What can the center conductor be made of?

solid copper or aluminum with a copper cladding (or coating).

What happens when the utility company suffers an outage?

standby and uninterruptible power supplies (UPSs) in the cable system switch on to keep RF signals flowing through the feeder.

What is the role of the dielectric?

supports the center conductor while providing insulation between the center conductor and aluminum sheath.

Describe the basic function of a headend.

takes all incoming signals and first processes them in some way, and then combines them to form a composite broadband RF signal that is sent out through the cable system.

What does the signal level meter do?

test video, audio, and data carriers to ensure that RF signals measure at the appropriate power level. In the feeder network, the SLM often is used to balance amplifier output levels and measure sources of signal leakage.

What is the benefit of replacing coax with fiber?

the HFC architecture reduces the number of amplifiers required to transport the signal to the feeder. Because of this reduction, the network is more reliable and provides better voice, video, and data signal quality. An HFC system provides a more efficient upstream path because separate fibers are used.

What must be done for grounding and bonding to be effective?

the bonding wire connected to the ground block must be of a lower resistance than the drop cable outer conductor.

What must be done before underground construction can begin?

the broadband cable operator must know where existing cables and pipes (electric, gas, water, and phone) are buried.

Once a trench is completed, how can the cable be placed?

the cable can be placed inside a conduit (or large pipe) or direct buried (without a conduit).

What underground procedure is followed instead of direct burial?

the company may bury underground conduit or pipe for greater protection of the cable.

What is the leading competitor to cable modem service in the home?

the digital subscriber line. This service is offered by the local phone company on an existing copper twisted-pair network.

Where does the feeder begin and end in a fiber-to-the-feeder architecture?

the feeder begins at the RF amplifier inside an optical node. Just as in a tree-and-branch design, the feeder ends at the drop port of a distribution tap.

What does an optical node on a two-way network contain?

the optical node contains optical receivers, upstream path transmitters, and forward and return RF amplifiers.

What happens after the cable is placed in the trench?

the span ends are routed out of the ground at specified device locations, such as amplifiers, optical nodes, and taps. Then the trench is backfilled with soil, and pedestal enclosures or underground vaults placed over the cable ends. Amplifiers and passive devices are mounted on support brackets within the enclosures and spliced onto the cables.

Through what devices does the downstream signal pass in the feeder?

through the feeder network until ending at a distribution tap. The signal can enter a tap either directly at the bridger amplifier or after passing through feeder cable, splitters, directional couplers, line extender amplifiers, and other distribution taps.

TDR

time domain reflectometer

What is one way to avoid aerial trespass, which occurs when the drop cable crosses property lines?

to install the cable from the tap to a midspan clamp and then to the contact point.

What are several unexpected dangers in the work environment?

unfriendly dogs and ill-behaved children, wasp nests on utility poles, poisonous spiders and snakes in crawl spaces, and disease-carrying pests in basements and attics.

How do standby supplies provide voltage during a power utility outage?

use 12-volt backup batteries and an AC inverter to provide voltage even during a power utility outage.

How do technicians balance amplifier levels?

use SLMs as well as plug-in attenuator pads and equalizers. Pads and equalizers adjust the input signal levels to create the desired output signal level. Balancing also ensures that technical system performance parameters remain within design specification.

What is Wifi?

usually limited to a distance of 300 feet from an internal base station

What were the objectives of the telecommunications of act of 1996?

were to allow any company to enter any telecommunications business and to grant permission for any provider to compete in any market

When do nonstandby power supplies operate?

when electricity is fed to them by the utility company, but these supplies stop working during low-voltage conditions or a utility power outage.

How do customer service and installation work with the marketing department?

with feedback regarding customer dissatisfaction with current programming and requests for new and different programming.