• Identify the characteristics of wireline transmission
• Describe the properties and uses of coaxial cable
• Describe the properties and uses of different types of twisted-pair wire
• Identify the characteristics of lightwave transmission
• Describe the properties and uses of fiber optic cable
• Identify factors to consider when selecting a telecommunications medium
• Explain and apply cabling standards
• Describe best practices for installing wire and fiber optic cabling
• Identify techniques for testing the continuity and performance of physical transmission media
15 comments:
Characteristics of wireline transmission are: Impedance, Propagation Delay and Latency, Distortion and Noise.
Properties and uses of coax: Consists of a central copper core surrounded by a plastic insulator, a braided metal shielding called braiding and outer plastic cover called a sheath. Used in early data networking but most commonly used for cable TV installations.
Properties of Fiber: Central fiber with a layer of glass cladding covered by a plastic buffer and strands of Kevlar which is then cover by a plastic sheath. Fiber is used to connect LANs or within a LAN, connects NAPs and Class 1 central offices.
Factors to consider when selecting a telecommunications medium: how well it integrates with the existing infrastructure, throughput potential, cost of installation and maintenance, scalability, security, and how well it resists the effects of noise.
The best practice for installing cable is to follow the TIA/EIA 568 specifications and the manufacturer's recommendations. Be careful not to exceed a cable's bend radius, subject it to heat or pressure, or untwist wire pairs more than one-half inch.
Factors to consider when selecting a transmission medium include: how well it integrates with the existing infrastructure, throughput potential, cost of installation and maintenance, scalability, security, and how well it resists the effects of noise.
One important tool for testing cables is the coninuity tester, which indicates whether a cable is transmitting current efficiently from one end to another.
In addition to attenuation, resistance, and voltage, characteristics that affect wireline transmission include impedance changes, latency, delay distortion, and noise. Any of all of these may affect a wireline transmission and increase its attenuation or loss, resulting in data errors.
Wireline characteristics that affect transmission are resistance, voltage, latency, delay, distortion, and noise. All of these will increase or decrease attenuation, loss, and data errors.
Lightwave characteristics that affect transmission are reflection, refraction, and absorption. All of these will increase or decrease attenuation, distortion delay, and data loss.
Cabling standards are documented agreements containing specifications and other precise criteria that stipulate how cabling should be designed and installed.
The factors to consider when selecting a transmission medium are integration with existing infrastructure, throughput, cost, scalability, security, and resistance to noise.
L. Campbell
2. Coaxial cable is used in cable tv systems. It used to be used for data networks but has since been outdated by twisted-pair cabling. coaxial has a central copper core surrounded by an braiding (metal or foil insulator), and a sheath.
3. Twisted-pair cabling comes in two types:
Shielded- twisted wire pairs that are not only individually insulated but also surrounded by a shielding.
unshielded- one or more insulated wire pairs encased in a sheath. The difference is that unshielded does not contain individual sheath's around the wire pairs. UTP is commenly used in telephone lines at a minimum of Cat3, Cat 5 is used in modern networks or advanced telephone systems.
6. Factors to consider when choosing a telecommunications medium include existing infrastructure, throughput potential, cost of installation, maintanance costs, noise immunity, security, and size and scalability.
9. Continuity testers, or cable checkers, determine whether your cabling cna provide connectivity. They send a small voltage to each conductor at one end of the cable, then check the other end to detect the voltage, or on other conductors in cable.
Performance testers perform the same as a continuity tester but also measure the length of each wire pair, ensures cable doesn't extend recommended max length, measure attenuation, crosstalk, termination resistance and impedance, and return loss. It also issues pass/fail rating for CAT3, 5, 6, and 7 standards. The performacne testers can save and print cable testing results.
Characteristic of wireline
uses electricity to sent data on a copper wire.Some characteristics of wireline transmissions are:
1)Impedance-amount of opposistion current will experience as it travels over a network.
2)Propagation Delay-The amount of time it takes a packet to travel from one point of the network to another point.
3)Noise-Unwanted interference for external sources that can degrade or distort a packet.
Coaxial Cable
Coax consists of a central copper wire that is shielded by brading and is covered in an outer plastic called a sheath and coax is mostly used for cable TV and in the early 1980 for network transmission.
Lightwave Transmission
Fiber optic cable that uses pulses of light to send data down a glass tube. Pure glass tube can accept up to 1 billion pulses per second and is resistant to noise.
Properties of Fiber Optics
Contains one or more tubes of glass in the core. Data is sent through pulses light by a laser or LED. Fiber come in to choices of single mode which uses a laser to transmit data and is faster, or multimode fiber, which uses the LED to trnanmit data at a slower rate. Single mode fiber is mostly used for the backbone of a network and multimode fiber is use for desktop connection.
Describe the properties & uses of coaxial cable: It uses cooper, and is used in cable tv, data communications, and is now being used for voice communications.
Describe the properties & uses of different types of twisted-pair wire: the use cooper and one is shielded, one is not. The are used in data and voice communications.
Describe the properties & uses of fiber optic cable: It uses glass which sends light and not electrons. It is used in a wide varieties of usages.
Id factors to consider when selecting a telecom. medium: You want to know the distance it has to go, the services it will be carry & should it be run on top or in ground.
1)Wireline transmission uses electricity for transmission. That makes wireline transmission susceptible to all the principles of electricity. Things like impedance, noise, distortion.
2)Twisted pair cable is used to help prevent near-end crosstalk and other noise. The higher the twist ratio, the more resistant the cable is to noise. There is two types of twisted pair cable,STP,and UTP. STP has a metal shielding which makes it resistant to external electromagnetic forces.UTP is less expencive, but less resistant to external noise.
3)Lightwaves experience virtually no resistance over fiber medium. Therefore,lightwave can be transmitted at much higher speeds. Lightwave transmissiom is not affected by EMI or RFI.
4)Fiber optic cable contains one or several glass fibers in its core. There are two types of fiber, single-mode,and multimode.
Songle-mode fiber transmissions can travel farther without being repeated.
Steve Jones says:
The properties of coaxial cable are simple. It consists of a central copper core surrounded by an insulator, a foil or braided metal shielding, and an outer cover. Where the center is copper the insulation is usually PVC or teflon. This insulation is needed to protect the copper core from coming in contact with the foil/braided metal shielding to prevent short-circuits. The jacket/outer cover protects the cable from physical damage. Uses of coax cable today mainly fall in the cable tv industry. That I believe is due to their large infrastructure.
When talking about twisted-pair wire there are two types unshielded and shielded. The shielded is similar to coax in that it to has foil covering its tristed pairs. This foil helps in shielding the twisted pairs from external electromagnetic forces. Reducing there effects on the inside twisted pair. Unshielded twisted-pair has no foil shielding making it more vulnerable to outside noise. Mainly due to cost the UTP is widely used within a wide variety of environments and for a variety of purposes.
The characteristics of wireline transmission is simply that it relys on wire to be transmitted. This wire is used to carry signals as voltage. Unlike fiber that uses glass and light.
Lightwave transmission carries discreet pulses of light instead of voltage like the wireline. The lightwave can be transmitted further and faster than wire due to it having virtually no resistance.
A coaxial cable consists of a central copper core surrounded by an insulator, foil or braided metal shielding called and an outer cover called the sheath. The core carries the signal, the shielding acts as a shield against noise and provides a ground. The insulation is usually made of Teflon. It protects the copper core from short-circuiting. The sheath, or jacket protects the cable from physical damage and is often PVC or a more expensive, fire-resistant plastic.
Coaxial cable supplies cable TV and data signals to many residences.
Twisted pair cables consist of shielded twisted pair(STP) and unshielded twisted pair(UTP). Both have 2 wires in each pair that are twisted together. All the pairs are encased in a plastic sheath. The twists in the wire is to prevent near-end crosstalk. The more twists per inch, the more resistant the pair is to all forms of noise.
Shielded twisted pair consists of twisted wire pairs that are individually insulated but also surrounded by a shielding made of a metallic substance such as foil. The shielding is a barrier to electromagnetic forces.
Unshielded twisted pair cabling consists of one or more insulated wire pairs encased in a plastic sheath. It doesn't contain additional shilding for the twisted pairs.
Twisted pair cables are used in consumer telephone wire and network cables.
Fiber optic cable contains one or more glass fibers in its core. Data is transmitted through pulsing light sent from a laser or LED. Around the fibers is a layer of glass called cladding. It acts as a mirror, reflecting light bak to the core in patterns that differ depending on the transmission mode(either single mode or multimode). This reflection allows the light to bend around corners without any loss of the signal. Strands of Kevlar surround the plastic bufer to prevent the cable from stretching.
Single-mode fiber uses a narrow core through which light generated by a laser travels over one path. Since light comes from a single point and refracts, the light doesn't disperse as the signal travels along the fiber. This allows single-mode to handle high bandwidths and long distances before requiring repeaters. It is often used to connect a carrier's two facilities but is too expensive to be used on normal data networks.
Multimode fiber contains a core with a larger diameter than single mode fiber over which many pulses of light generated by a LED. Since light is being reflected many different ways(total internal reflection), the waves become less distinguishable the longer the distance they travel. It is used for shorter distances. It is often used for backbone cables.
Transmission over fiber optic cable carries discreet pulses of light. The light experiences almost no resistance so they can be transmitted at faster rates than voltage-based signals. Since it doesn't use electrical current, it isn't susceptible to EMI or RFI. It can span large distances before it requires a repeater. Fiber optics takes advantage of reflection. It takes into account refraction and absorption which can cause attenuation, distortion and loss. The tips of a fiber optic connector must be kep clean to improve performance because small particles can affect the transmission of light.
Some characteristics of wireline transmission are: attenuation resistance,voltage,impedance changes,latency,delay distortion, and noise.
Properties and uses of coaxial cable consists coppercore plastic surrounded by braided metal shielding.It also has outer plastic cover known as the sheath.
Used primarly for guide radio frequencies.
Fiber optic cable contains one or several glass fibers in its core. Outside the fiber is a layer of glass called cladding its acts as a mirror reflecting the light back to its core. Data is transmitted via light pulses sint from a laser.
Uses of fiber are the transmission of data via light pulses.
Twisted pair cabling consist of of color coded pairs in insulated copper wires. With twist to reduce noise. (STP) contains foil shielding to reduce crosstalk. (UTP) does not have contain shielding. it is less expensive. Both are used to transmit data.
John Otey
1. Coaxial Cable-Uses a central copper core surrounded by an insulator, and metal braided shielding known as braiding and then an outer cover known as the sheath, or jacket. It carries signals farther than twisted-pair cabling before amplification of signals was necessary. Coaxial cable is assigned an RG specification number. Some tend to vary depending on their use of core materials. This can influence their impendence, and throughput.
2. Fiber Optic Cable-Contains one of several glass fibers in its core. It provides near unlimited throughput, high resistance to noise, and top inherent security. Fiber also sends signals further than coax, or twisted-pair cable. This is due to there being fewer number of repeaters.
3. Lightwave Transmission-Can be transmitted faster and more reliably than a voltage-based signal. Fiber cabling is designed to take advantage of light's tendency to reflect.
4. Twisted Pair Cabling-Is twisted around each other to form pairs. Each different pair is twisted slightly more or less than an another. In unshielded twisted pair, it is insulated and in encases in a plastic sheath. Unlike other twisted pair, it does not contain additional shielding for twisted pairs.
1. Describe properities, uses fiber
optics? Denies electrical pulse
since it emits light not elec-
tricity for transmissions, pro-
vides greater bandwidth. Comes
in several thickness(size) to
include multi-mode and single
mode. Carries longer distances,
about equal value(cost) for in-
stallations. Does have to be
enclosed and protected but for
different reasons, mostly for
signal loss(light) to connectors
and breaks.
1. Wireline Transmission:
Impedance - the resistance of of a circuit or wire as it pertains to AC voltage. Impedance can be measured in ohms, capacitive reactance, and inductive reactance.
Propagation delay - the time it takes for a signal to travel the length of the wire.
Distortion - any affect that alters the original signal and may include attenuation, delay, or phase distortion.
Noise - any external interference that distorts the original signal, such as EMI, RFI, crosstalk, impulse, and thermal noise. The amount of noise is expressed as the signal-to-noise ratio measured in dB's.
2. Lightwave Transmission: is the transmission of a signal through glass fiber using light waves. Unlike wire, fiber optic transmissions are immune to the all of the noise that affects wireline transmission with the exception of attenuation.
3. Selecting a medium:
When selecting a medium, factors to be considered are:
Does the current infrastructure meet any of the current requirements, can new media be integrated or should it all be replaced?
What is the required throughput or bandwidth?
How much is the budget for the project.
What will the cast of maintenance be? Will technician need to be trained in new techniques.
Noise requirements - if a lot of RFI and EMI are being produced, you should consider fiber.
How important is security? Wireline and wireless are most susceptible to eavesdropping while fiber optic is the most difficult to tap into.
Is there room to grow?
4. Testing:
If the cable is relatively short a multimeter or ohm meter can be used to test continuity. However, many cable runs may reach 300 ft. making it difficult to use a simple meter. For these circumstances there are specialized testers available known as continuity testers or cable checkers. A device is attached to both ends of the cable and the wires are checked for continuity.
A more sophisticated device may be used to check the performance of the circuit. These devices can check not only continuity but also wire length, attenuation, crosstalk, max frequency, and the distance to a fault in the wire.
John Nicol
Coaxial Cable supplies cable tv and data signals to many residences.It is also used to guide radio frequencies.It supports low throughput. Coaxial cable is made of sheath,braided metal sheilding, (pvc)or teflon, and a copper core.
Factors to consider:Existing Infrastructures, throughput potential, cost of installation, cost of maintenance, noise immunity, security, size and scalability.
Continuity tester apply a small voltage to each conductor at one end of the cable, and then check whether that voltage is detected at the other end. Uses a set of light that signal pass/fail.
Performance testers ensure cable does not exceed recommended max lengths, measures attenuation, and crosstalk.
1. Describe properties/uses fiber optics cable? Denies electrical pulse since it emits light not electricity for transmission of signal. Greater bandwidth but only one way transmission to mode, comes in different thickness(sizes)including multiple and signal mode, carries longer distances. About equal in cost for medium, installations. Does require insulation inclosed and protected from light sources at connectors and other guidelines due to travel
of light transmission and crimpping
or breaks. One way traffic per strand. Used horizontally, verically, infrastructure, and on LAN/WAN topology, in buildings and areas where foot traffic is low or significantly absent.
2. Factors to consider, selecting telecommunications medium? Maybe, cost effect, future growth, %of usage(traffic), maintenance perspective, and security for the most part to name a few items.
3. Explain/apply cabling standard?
Industry standard for compatibility
conventions and reliability guide. TIA/EIA and National Electric Code,
safeguard people and property with
standardizational structured cabling, enterprise-wide for maxi-
mum performance with minimal main-
tenance. Principally divided into 6
subsystems.
A. At entrance facilities from a LAN/WAN locations(far to close) need to a building to building entrance point.
B. Backbone interconnections of equipment room to the entrance as well as between buildings.
C. Equipment room distribution frame to servers, PBX, conference room, private network.
D. Telecommunication closet con-
nectivity device to printers, fax,
workstations, other equipment from
one to many termination.
E. Horizontal wiring to wall jack with other cabling type uses.
F. Work-area with a minimum one voice and data outlook devices.
Standard heirachical methods and vendor product remaining constant but growing tendencies.
4. Identify techniques for testing
continuity and performance of physical transmission media?
Testing is the first method used for trouble-shooting and tools used on newly installed or aged media. Eyeballs and noggin are your first tools implemented. The
methodoloy is a way by pattern.
* establish any changes as to what occur prior and after.
* determine hardware or software or both.
* recreate problem if possible but do not dig a bigger hole.
* identify by minimizing devices to a single point or software.
* impliment solution by planning, adding one item at a time.
* test, test, test.
* document everything.
using other tools may be required to further find a solution such as a exchanging/replacing, tone generator, tone locator, continuity
tester, performance testers, fiber optic cable tester, time domain
reflectometers, optical time domain
reflectometers, telephone test set, and who knows what other device is out there, if you do not know it is used, what good will it be.
Bernardo
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