assalamualaikum n salam sejahtera..
selamat hari raya maaf zahir batin saya ucapkan kepada semua..
catatan ni adalah untuk 30 september 2009...
mesti seronok kn bercuti mase hari raya..
bagi saya raya thn ni paling best skali sebab dapat jumpe semua family member n member2 lame..
best sgt...
yg penting duit raye still dpt lagi walaupun dah besar panjang..
hehehe..
tp yg xbestnye, cti raye pndk sgt ar n xsmpt nkpegi beraya..
whatever pun kenangan2 time raye akan selalu saya ingati..
untuk kali ini, cik azura telah menyuruh kami untuk menyenaraikan 10 jenis ayat2 pendek yg digunakan dalam sms...apa ye???dalam bm pn blh kn??
1. you - u
2. because - coz
3. the - d
4. kat mane - ktne
5. saya - sy
6. pergi - g
7. okey - k
8. tiada/tidak - x
9. and - n
10. good night - gudnite
oklah ni saje utk catatan kali ni..
maybe ni adalah post sy yg terakhir..
tapi insyaallah kalau ada masa lagi sy akan terus update blog ini..
doakan sy untuk exam nnt ye..
salam...
Wednesday, September 30, 2009
"RCA"
assalamualaikum..
catatan ini adalah untuk 13 september 2009..
cik azura telah menyuruh kami mencari apa itu RCA..
berikut merupakan maklumat yg saya perolehi mengenai RCA..
catatan ini adalah untuk 13 september 2009..
cik azura telah menyuruh kami mencari apa itu RCA..
berikut merupakan maklumat yg saya perolehi mengenai RCA..
RADIO CORPORATION OF AMERICA (RCA)
U.S. RADIO COMPANY
In 1919, General Electric (GE) formed a privately owned corporation to acquire the assets of the wireless radio company American Marconi from British Marconi. The organization, known as the Radio Corporation of America or RCA, was formally incorporated on 17 October of that year. Shortly thereafter, American Telephone and Telegraph (AT and T) and Westinghouse acquired RCA assets and became joint owners of RCA. In 1926, RCA formed a new company, the National Broadcasting Company (NBC), to oversee operation of radio stations owned by RCA, General Electric, Westinghouse and AT and T.
In the early 1930's, the Justice Department filed an antitrust suit against the company. In a 1932 consent decree, the organization's operations were separated and GE, AT and T, and Westinghouse were forced to sell their interests in the company. RCA retained its patents and full ownership of NBC. Shortly after becoming an independent company, RCA moved into new headquarters in the Rockefeller Center complex in New York City, into what later became known as Radio City.
While other American companies were cutting back on research expenditures during the depression years, David Sarnoff, President of RCA since 1930, was a staunch advocate of technological innovation. He expanded RCA's technology research division, devoting increased resources to television technology. Television pioneer Vladimir Zworykin was placed in charge of RCA's television research division. RCA acquired competing and secondary patents related to television technology, and once the organization felt that the technology had attained an appropriate level of refinement, it pushed for commercialization of the new medium.
In 1938, RCA persuaded the Radio Manufacturers Association (RMA) to consider adoption of its television system for standardization. The RMA adopted the RCA version, a 441 line, 30 pictures per second system, and presented the new standard to the FCC on 10 September 1938. Upon the recommendation of the RMA, the Federal Communications Commission (FCC) scheduled formal hearings to address the adoption of standards. The hearings, however, did not take place until January 1940.
In the interim, RCA began production of receivers and initiated a limited schedule of television programming from the New York transmitters of the National Broadcasting Corporation (NBC) basing their service upon the RMA-RCA standards. The service was inaugurated in conjunction with the opening of the New York World's Fair on 30 April 1939 and continued throughout the year. At the commission's hearing addressing standards on 15 January 1940, opposition to the proposed RMA standards emerged. The two strongest opponents of the standard were DuMont Laboratories and Philco Radio and Television. One of the criticisms voiced by both organizations was the assertion that the 441 line standard did not provide sufficient visual detail and definition. Given the lack of a clear industry consensus, the Commission did not act on the proposed RMA standards.
Despite the absence of official approval, RCA continued to employ the RMA standards and announced plans in early 1940 to increase production of television receivers, cut the price to consumers by one-third, and double their programming schedule. While some commentators saw this as a reasonable and progressive action, the Commission perceived it as a step towards prematurely freezing the standards in place, and as a consequence, scheduled another set of public hearings for 8 April 1940. At these hearings, opponents argued that the action taken by RCA was stifling research and development into other alternative standards. As a result of the hearings, the Commission eliminated commercial broadcasting until further development and refinement had transpired. Furthermore, the Commission asserted that commercialization of broadcasting would not be permitted until there was industry consensus and agreement on one common system. To marshal industry wide support for a single standard, the RMA formed the National Television System Committee (NTSC). The NTSC standards, a 525 line, 60 fields per second system, were approved by the FCC in 1941.Several years later, RCA also became a major participant in the establishment of color television standards. In 1949, the organization proposed to the FCC that its dot sequential color system, which was compatible with existing black and white receivers, be adopted as the new color standard. Citing shortcomings in the compatible systems offered by RCA and other organizations, the FCC opted to formally adopt an incompatible color system offered by the Columbia Broadcasting System as the color standard. RCA appealed this decision all the way to the Supreme Court, while simultaneously refining their color system. A second NTSC was formed to examine the color issue. In 1953, the FCC reversed itself and endorsed a modified version of the RCA dot sequential system compatible color system offered by the NTSC.
In the 1950s, RCA continued the military and defense work in which it had been heavily engaged during World War II. In the late 1950s and early 1960s, the company became involved with both satellite technology and the space program. During the 1960s, RCA began to diversify as the company acquired such disparate entities as the publishing firm Random House, and the car rental company Hertz. Throughout the 1970s and early 1980s, RCA began to divest itself of many of its acquired subsidiaries. In June 1986, RCA was acquired by General Electric, the organization that had originally established it as a subsidiary. GE retained the brand name RCA, established NBC as a relatively autonomous unit, and combined the remainder of RCA's businesses with GE operations.
Wednesday, September 9, 2009
"hari yg baru"
hari ni 090909...
menarik kan tarikh ni...
tapi xde ap yg menarik utk dibuat..
oklah, mse dlm kls, kteorang smbg blk blaja bab telekomunikasi...
ada 2 lg subtopik iaitu fax dan pager..
cik azura juga ada memberitahu serba sedikit apa yg akan keluar time final nnt..
tp yg pntg adalah kuiz kedua yg akan dibuat pada 14 oktober 2009..
berita yg kedua adalah pada hari rabu, 16 sep 2009 kls dibatalkan...
tapi bkn blh blk awl pn...
tkt dh bli utk 17 hb....
frust jgk ar...
walaupun kls btl, tp still kene bgn pg coz pd hari 2 ada kelas kul 8...
huhuhu....
terima je la....
hehehe...
whatever pn sy akan pg jugak kls pd hari rabu...
salam n tggu catatan yg seterusnya...
adios....
menarik kan tarikh ni...
tapi xde ap yg menarik utk dibuat..
oklah, mse dlm kls, kteorang smbg blk blaja bab telekomunikasi...
ada 2 lg subtopik iaitu fax dan pager..
cik azura juga ada memberitahu serba sedikit apa yg akan keluar time final nnt..
tp yg pntg adalah kuiz kedua yg akan dibuat pada 14 oktober 2009..
berita yg kedua adalah pada hari rabu, 16 sep 2009 kls dibatalkan...
tapi bkn blh blk awl pn...
tkt dh bli utk 17 hb....
frust jgk ar...
walaupun kls btl, tp still kene bgn pg coz pd hari 2 ada kelas kul 8...
huhuhu....
terima je la....
hehehe...
whatever pn sy akan pg jugak kls pd hari rabu...
salam n tggu catatan yg seterusnya...
adios....
"6 september 2009"
hari ini kami belajar seperti biasa..
cik azura menyambung kembali bab telekomunikasi..
didalam bab ini terdapat lagi 2 subtopik selain daripada satelit dan terdiri daripada...
1. telefon
2. mobile phone
selain itu cik azura juga mengingatkan mengenai tugasan yg perlu dihantar pada 13 sep 2009.
sekian je utk kali ni...
salam..
cik azura menyambung kembali bab telekomunikasi..
didalam bab ini terdapat lagi 2 subtopik selain daripada satelit dan terdiri daripada...
1. telefon
2. mobile phone
selain itu cik azura juga mengingatkan mengenai tugasan yg perlu dihantar pada 13 sep 2009.
sekian je utk kali ni...
salam..
"the Razak sats"
2 september 2009..
kami belajar tjk baru iaitu telekomunikasi..
kami juga disuruh untuk mencari maklumat mengenai Razak sats..
berikut merupakan beberapa maklumat mengenai Razak sats...
The objectives of the project are to provide high-resolution images for Malaysia and build Malaysian space technology capabilities through ATSB®. In order to meet the technology objective, a cost-effective high resolution imaging system for Earth observation specifically for a small satellite less than 200 kg was implemented. RazakSAT® carries the Medium-sized Aperture Camera (MAC) that will provide 2.5m resolution panchromatic and 5.0m resolution multi-spectral images. This project involves the design, development, launch and operations of the satellite.
The RazakSAT® satellite is planned to be launched near in the future on a USA launcher Falcon 1 owned and operated by the company Space Exploration Technologies (SpaceX). It will be a dedicated launch from kwajalein in the Republic of Marshall Islands which is situated very close to the equator to give the best orbital injection for RazakSAT® , i.e. near equatorial orbit (NEqO). RazakSAT®s images would be applied to forestry, fishery, migration and other areas that will benefit the nation.
It carries an electro-optical payload, a Medium-sized Aperture Camera (MAC) a pushbroom camera with 5 linear detectors (1 panchromatic, 4 multi-spectral). The RazakSAT® satellite will be operated through its ground segment in Malaysia, consisting of a Mission Control Station (MCS) and Image Receiving and Processing Station (IRPS). ATSB®'s engineers are operators at the MCS and they will execute the mission plan, command generation and telemetry receiving, archiving and analysis.
ATSB® is also involved in Sg Lang Ground Station implementation project committee. ATSB® has assisted in development of the system specification to support RazakSAT® Mission Control Station (MCS) and Image Receiving and Processing Station (IRPS).
kami belajar tjk baru iaitu telekomunikasi..
kami juga disuruh untuk mencari maklumat mengenai Razak sats..
berikut merupakan beberapa maklumat mengenai Razak sats...
The objectives of the project are to provide high-resolution images for Malaysia and build Malaysian space technology capabilities through ATSB®. In order to meet the technology objective, a cost-effective high resolution imaging system for Earth observation specifically for a small satellite less than 200 kg was implemented. RazakSAT® carries the Medium-sized Aperture Camera (MAC) that will provide 2.5m resolution panchromatic and 5.0m resolution multi-spectral images. This project involves the design, development, launch and operations of the satellite.
The RazakSAT® satellite is planned to be launched near in the future on a USA launcher Falcon 1 owned and operated by the company Space Exploration Technologies (SpaceX). It will be a dedicated launch from kwajalein in the Republic of Marshall Islands which is situated very close to the equator to give the best orbital injection for RazakSAT® , i.e. near equatorial orbit (NEqO). RazakSAT®s images would be applied to forestry, fishery, migration and other areas that will benefit the nation.
It carries an electro-optical payload, a Medium-sized Aperture Camera (MAC) a pushbroom camera with 5 linear detectors (1 panchromatic, 4 multi-spectral). The RazakSAT® satellite will be operated through its ground segment in Malaysia, consisting of a Mission Control Station (MCS) and Image Receiving and Processing Station (IRPS). ATSB®'s engineers are operators at the MCS and they will execute the mission plan, command generation and telemetry receiving, archiving and analysis.
ATSB® is also involved in Sg Lang Ground Station implementation project committee. ATSB® has assisted in development of the system specification to support RazakSAT® Mission Control Station (MCS) and Image Receiving and Processing Station (IRPS).
"uhu..."
ini adalah catatan utk 30 ogos 2009..
cik azura menyuruh kami mencari mengenai 2 topology iaitu topology mesh dan tree...
MESH TOPOLOGY
A type of network setup where each of the computers and network devices are interconnected with one another, allowing for most transmissions to be distributed, even if one of the connections go down. This type of topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this type of topology is commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology.
TREE TOPOLOGY
Among all the Network Topologies we can derive that the Tree Topology is a combination of the bus and the Star Topology. The tree like structure allows you to have many servers on the network and you can branch out the network in many ways. This is particularly helpful for colleges, universities and schools so that each of the branches can identify the relevant systems in their own network and yet connect to the big network in some way.
cik azura menyuruh kami mencari mengenai 2 topology iaitu topology mesh dan tree...
MESH TOPOLOGY
A type of network setup where each of the computers and network devices are interconnected with one another, allowing for most transmissions to be distributed, even if one of the connections go down. This type of topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this type of topology is commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology.
TREE TOPOLOGY
Among all the Network Topologies we can derive that the Tree Topology is a combination of the bus and the Star Topology. The tree like structure allows you to have many servers on the network and you can branch out the network in many ways. This is particularly helpful for colleges, universities and schools so that each of the branches can identify the relevant systems in their own network and yet connect to the big network in some way.
Tuesday, September 1, 2009
"26 ogos 2009"
Main article: Electromagnetic shielding
S/UTP cable format
S/UTP, also known as FTP
S/STP, also known as S/FTP.
STP cable format
Twisted pair cables are often shielded in attempt to prevent electromagnetic interference. Because the shielding is made of metal, it may also serve as a ground. However, usually a shielded or a screened twisted pair cable has a special grounding wire added called a drain wire. This shielding can be applied to individual pairs, or to the collection of pairs. When shielding is applied to the collection of pairs, this is referred to as screening. The shielding must be grounded for the shielding to work.
Screened unshielded twisted pair (S/UTP)
Also known as Fully shielded[citation needed] (or Foiled) Twisted Pair (FTP), is a screened UTP cable (ScTP).
Shielded twisted pair (STP or STP-A)
STP cabling includes metal shielding over each individual pair of copper wires. This type of shielding protects cable from external EMI (electromagnetic interferences). e.g. the 150 ohm shielded twisted pair cables defined by the IBM Cabling System specifications and used with token ring networks.
Screened shielded twisted pair (S/STP or S/FTP)
S/STP cabling, also known as Screened Fully shielded Twisted Pair (S/FTP), [1] is both individually shielded (like STP cabling) and also has an outer metal shielding covering the entire group of shielded copper pairs (like S/UTP). This type of cabling offers the best protection from interference from external sources, and also eliminates alien crosstalk
Unshielded twisted pair (UTP) scct1043 group a
Unshielded twisted pair
Twisted pair cables were first used in telephone systems by Alexander Graham Bell in 1881. By 1900, the entire American telephone line network was either twisted pair or open wire with similar arrangements to guard against interference. Today, most of the millions of kilometres of twisted pairs in the world are outdoor landlines, owned by telephone companies, used for voice service, and only handled or even seen by telephone workers.
UTP cables are found in many ethernet networks and telephone systems. For indoor telephone applications, UTP is often grouped into sets of 25 pairs according to a standard 25-pair color code originally developed by AT&T. A typical subset of these colors (white/blue, blue/white, white/orange, orange/white) shows up in most UTP cables.
For urban outdoor telephone cables containing hundreds or thousands of pairs, the cable is divided into smaller but identical bundles. Each bundle consists of twisted pairs that have different twist rates. The bundles are in turn twisted together to make up the cable. Pairs having the same twist rate within the cable can still experience some degree of crosstalk. Wire pairs are selected carefully to minimize crosstalk within a large cable.
Unshielded twisted pair cable with different twist rates
UTP cable is also the most common cable used in computer networking. Ethernet, the most common data networking standard, utilizes UTP cables. Twisted pair cabling is often used in data networks for short and medium length connections because of its relatively lower costs compared to optical fiber and coaxial cable.
UTP is also finding increasing use in video applications, primarily in security cameras. Many middle to high-end cameras include a UTP output with setscrew terminals. This is made possible by the fact that UTP cable bandwidth has improved to match the baseband of television signals. While the video recorder most likely still has unbalanced BNC connectors for standard coaxial cable, a balun is used to convert from 100-ohm balanced UTP to 75-ohm unbalanced. A balun can also be used at the camera end for ones without a UTP output. Only one pair is necessary for each video signal.
kelebihan dan kelemahan 'coxtail cable, fibre optic and twisted pair.....Coaxial Cable:
Coaxial cable is made of two conductors that share the same axis; the center is a copper wire that is insulated by a plastic coating and then wrapped with an outer conductor (usually a wire braid). This outer conductor around the insulation serves as electrical shielding for the signal being carried by the inner conductor. A tough insulating plastic tube outside the outer conductor provides physical and electrical protection. At one time, coaxial cable was the most widely used network cabling. However, with improvements and the lower cost of twisted-pair cables, it has lost its popularity.
Network Cable Types
There are two types of coaxial cable.
1. ThickNet
2. ThinNet
ThickNet:
ThickNet is about .38 inches in diameter. This makes it a better conductor, and it can carry a signal about 1640 feet (500 meters) before signal strength begins to suffer. The disadvantage of ThickNet over ThinNet is that it is more difficult to work with. The ThickNet version is also known as standard Ethernet cable.
ThinNet:
ThinNet is the easiest to use. It is about .25 inches in diameter, making it flexible and easy to work with (it is similar to the material commonly used for cable TV). ThinNet can carry a signal about 605 feet (185 meters) before signal strength begins to suffer.
Twisted-Pair Cable:
Twisted-pair cable consists of two insulated strands of copper wire twisted around each other to form a pair. One or more twisted pairs are used in a twisted-pair cable. The purpose of twisting the wires is to eliminate electrical interference from other wires and outside sources such as motors. Twisting the wires cancels any electrical noise from the adjacent pair. The more twists per linear foot, the greater the effect.
Network Cable Types
There are two types of twisted pair cable
1. Shielded Twisted Pair (STP)
2. Unshielded Twisted Pair (UTP)
Shielded Twisted Pair (STP):
The only difference between STP and UTP is that STP has a foil or wire braid wrapped around the individual wires of the pairs. The shielding is designed to minimize EMI radiation and susceptibility to crosstalk. The STP cable uses a woven-copper braided jacket, which is a higher-quality, more protective jacket than UTP.
Unshielded Twisted Pair (UTP):
As the name implies, "unshielded twisted pair" (UTP) cabling is twisted pair cabling that contains no shielding. UTP cables can be divided further into following categories:
Category 1 : Traditional telephone cable. Carries voice but not data
Category 2 : Certified UTP for data transmission of up to 4 megabits per second (Mbps). It has four twisted pairs
Category 3 : Certified UTP for data transmission of up to 10 Mbps. It has four twisted pairs
Category 4 : Certified UTP for data transmission of up to 16 Mbps. It has four twisted pairs
Category 5 : Certified for data transmission of up to 100 Mbps. It has four twisted pairs of copper wire
Category 6 :Offers transmission speeds up to 155 Mbps
Category 7 :Category 7 is a proposed standard that aims to support transmission at frequencies up to 600 MHz
Twisted-pair cable has several advantages over other types of cable (coaxial and fiberoptic): It is readily available, easy to install, and inexpensive. Among its disadvantages are its sensitivity to electromagnetic interference (EMI), its susceptibility to eavesdropping, its lack of support for communication at distances of greater than 100 feet, and its requirement of a hub (multiple network connection point) if it is to be used with more than two computers. Twisted pair cables use RJ45 connector.
Fiberoptic Cable:
Fiberoptic cable is made of light-conducting glass or plastic fibers. It can carry data signals in the form of modulated pulses of light. The plastic-core cables are easier to install but do not carry signals as far as glass-core cables. Multiple fiber cores can be bundled in the center of the protective tubing.
Network Cable Types
When both material and installation costs are taken into account, fiberoptic cable can prove to be no more expensive than twisted-pair or coaxial cable. Fiber has some advantages over copper wire: It is immune to EMI and detection outside the cable and provides a reliable and secure transmission media. It also supports very high bandwidths (the amount of information the cable can carry), so it can handle thousands of times more data than twisted-pair or coaxial cable.Cable lengths can run from .25 to 2.0 kilometers depending on the fiberoptic cable and network. If you need to network multiple buildings, this should be the cable of choice. Fiberoptic cable systems require the use of fiber-compatible NICs.
S/UTP cable format
S/UTP, also known as FTP
S/STP, also known as S/FTP.
STP cable format
Twisted pair cables are often shielded in attempt to prevent electromagnetic interference. Because the shielding is made of metal, it may also serve as a ground. However, usually a shielded or a screened twisted pair cable has a special grounding wire added called a drain wire. This shielding can be applied to individual pairs, or to the collection of pairs. When shielding is applied to the collection of pairs, this is referred to as screening. The shielding must be grounded for the shielding to work.
Screened unshielded twisted pair (S/UTP)
Also known as Fully shielded[citation needed] (or Foiled) Twisted Pair (FTP), is a screened UTP cable (ScTP).
Shielded twisted pair (STP or STP-A)
STP cabling includes metal shielding over each individual pair of copper wires. This type of shielding protects cable from external EMI (electromagnetic interferences). e.g. the 150 ohm shielded twisted pair cables defined by the IBM Cabling System specifications and used with token ring networks.
Screened shielded twisted pair (S/STP or S/FTP)
S/STP cabling, also known as Screened Fully shielded Twisted Pair (S/FTP), [1] is both individually shielded (like STP cabling) and also has an outer metal shielding covering the entire group of shielded copper pairs (like S/UTP). This type of cabling offers the best protection from interference from external sources, and also eliminates alien crosstalk
Unshielded twisted pair (UTP) scct1043 group a
Unshielded twisted pair
Twisted pair cables were first used in telephone systems by Alexander Graham Bell in 1881. By 1900, the entire American telephone line network was either twisted pair or open wire with similar arrangements to guard against interference. Today, most of the millions of kilometres of twisted pairs in the world are outdoor landlines, owned by telephone companies, used for voice service, and only handled or even seen by telephone workers.
UTP cables are found in many ethernet networks and telephone systems. For indoor telephone applications, UTP is often grouped into sets of 25 pairs according to a standard 25-pair color code originally developed by AT&T. A typical subset of these colors (white/blue, blue/white, white/orange, orange/white) shows up in most UTP cables.
For urban outdoor telephone cables containing hundreds or thousands of pairs, the cable is divided into smaller but identical bundles. Each bundle consists of twisted pairs that have different twist rates. The bundles are in turn twisted together to make up the cable. Pairs having the same twist rate within the cable can still experience some degree of crosstalk. Wire pairs are selected carefully to minimize crosstalk within a large cable.
Unshielded twisted pair cable with different twist rates
UTP cable is also the most common cable used in computer networking. Ethernet, the most common data networking standard, utilizes UTP cables. Twisted pair cabling is often used in data networks for short and medium length connections because of its relatively lower costs compared to optical fiber and coaxial cable.
UTP is also finding increasing use in video applications, primarily in security cameras. Many middle to high-end cameras include a UTP output with setscrew terminals. This is made possible by the fact that UTP cable bandwidth has improved to match the baseband of television signals. While the video recorder most likely still has unbalanced BNC connectors for standard coaxial cable, a balun is used to convert from 100-ohm balanced UTP to 75-ohm unbalanced. A balun can also be used at the camera end for ones without a UTP output. Only one pair is necessary for each video signal.
kelebihan dan kelemahan 'coxtail cable, fibre optic and twisted pair.....Coaxial Cable:
Coaxial cable is made of two conductors that share the same axis; the center is a copper wire that is insulated by a plastic coating and then wrapped with an outer conductor (usually a wire braid). This outer conductor around the insulation serves as electrical shielding for the signal being carried by the inner conductor. A tough insulating plastic tube outside the outer conductor provides physical and electrical protection. At one time, coaxial cable was the most widely used network cabling. However, with improvements and the lower cost of twisted-pair cables, it has lost its popularity.
Network Cable Types
There are two types of coaxial cable.
1. ThickNet
2. ThinNet
ThickNet:
ThickNet is about .38 inches in diameter. This makes it a better conductor, and it can carry a signal about 1640 feet (500 meters) before signal strength begins to suffer. The disadvantage of ThickNet over ThinNet is that it is more difficult to work with. The ThickNet version is also known as standard Ethernet cable.
ThinNet:
ThinNet is the easiest to use. It is about .25 inches in diameter, making it flexible and easy to work with (it is similar to the material commonly used for cable TV). ThinNet can carry a signal about 605 feet (185 meters) before signal strength begins to suffer.
Twisted-Pair Cable:
Twisted-pair cable consists of two insulated strands of copper wire twisted around each other to form a pair. One or more twisted pairs are used in a twisted-pair cable. The purpose of twisting the wires is to eliminate electrical interference from other wires and outside sources such as motors. Twisting the wires cancels any electrical noise from the adjacent pair. The more twists per linear foot, the greater the effect.
Network Cable Types
There are two types of twisted pair cable
1. Shielded Twisted Pair (STP)
2. Unshielded Twisted Pair (UTP)
Shielded Twisted Pair (STP):
The only difference between STP and UTP is that STP has a foil or wire braid wrapped around the individual wires of the pairs. The shielding is designed to minimize EMI radiation and susceptibility to crosstalk. The STP cable uses a woven-copper braided jacket, which is a higher-quality, more protective jacket than UTP.
Unshielded Twisted Pair (UTP):
As the name implies, "unshielded twisted pair" (UTP) cabling is twisted pair cabling that contains no shielding. UTP cables can be divided further into following categories:
Category 1 : Traditional telephone cable. Carries voice but not data
Category 2 : Certified UTP for data transmission of up to 4 megabits per second (Mbps). It has four twisted pairs
Category 3 : Certified UTP for data transmission of up to 10 Mbps. It has four twisted pairs
Category 4 : Certified UTP for data transmission of up to 16 Mbps. It has four twisted pairs
Category 5 : Certified for data transmission of up to 100 Mbps. It has four twisted pairs of copper wire
Category 6 :Offers transmission speeds up to 155 Mbps
Category 7 :Category 7 is a proposed standard that aims to support transmission at frequencies up to 600 MHz
Twisted-pair cable has several advantages over other types of cable (coaxial and fiberoptic): It is readily available, easy to install, and inexpensive. Among its disadvantages are its sensitivity to electromagnetic interference (EMI), its susceptibility to eavesdropping, its lack of support for communication at distances of greater than 100 feet, and its requirement of a hub (multiple network connection point) if it is to be used with more than two computers. Twisted pair cables use RJ45 connector.
Fiberoptic Cable:
Fiberoptic cable is made of light-conducting glass or plastic fibers. It can carry data signals in the form of modulated pulses of light. The plastic-core cables are easier to install but do not carry signals as far as glass-core cables. Multiple fiber cores can be bundled in the center of the protective tubing.
Network Cable Types
When both material and installation costs are taken into account, fiberoptic cable can prove to be no more expensive than twisted-pair or coaxial cable. Fiber has some advantages over copper wire: It is immune to EMI and detection outside the cable and provides a reliable and secure transmission media. It also supports very high bandwidths (the amount of information the cable can carry), so it can handle thousands of times more data than twisted-pair or coaxial cable.Cable lengths can run from .25 to 2.0 kilometers depending on the fiberoptic cable and network. If you need to network multiple buildings, this should be the cable of choice. Fiberoptic cable systems require the use of fiber-compatible NICs.
"Opss....KUIZ!!!"
hai semua...
ini adalah catatan untuk 12 ogos 2009...
hari kami xblaja and cik azura pun xmsk kelas..
tapi seperti yg dijangkakan, kami ada kuiz hari ini..
kelas kami diambil alih oleh en. mod..
sebenarnya kuiz yg diberikan agak mudah namun tak tahu kenapa saya rasa mcm tak boleh jawab semua soalan..
hal ini mungkin kerana saya kurang stdy and tak fokus dalam kelas..
sya tak tahu apa yang perlu dijawab..
rasa mcm nak nangis pun ada sebab tak boleh jawab..
but anyway, saya try jugak buat soalan tu..
hrp2 cik azura tak marah dgn jawapan saya yg teruk tu..
huhuhuhu...
ini adalah catatan untuk 12 ogos 2009...
hari kami xblaja and cik azura pun xmsk kelas..
tapi seperti yg dijangkakan, kami ada kuiz hari ini..
kelas kami diambil alih oleh en. mod..
sebenarnya kuiz yg diberikan agak mudah namun tak tahu kenapa saya rasa mcm tak boleh jawab semua soalan..
hal ini mungkin kerana saya kurang stdy and tak fokus dalam kelas..
sya tak tahu apa yang perlu dijawab..
rasa mcm nak nangis pun ada sebab tak boleh jawab..
but anyway, saya try jugak buat soalan tu..
hrp2 cik azura tak marah dgn jawapan saya yg teruk tu..
huhuhuhu...
"9 OGOS 2009"
assalammualaikum...
maaf sebab lambat update blog ni..
sejujurnya saya tidak begitu berminat untuk kerja-kerja yg perlu di update selalu..
but anyway, saya akan try utk terus mengemaskinikan blog ini..
saya minta maaf byk2 terutama kpd cik azura coz selalu lambat update blog ni..
ini adalah cerita mengenai kelas pada 9 Ogos 2009 iaitu pada hari Ahad..
hari ni kelas masih berjalan seperti biasa dan masih belajar dengan tajuk yg baru..
namun begitu cik azura ada mengingatkan kami untuk bersedia bagi menghadapi kuiz..
tarikhnya tidak diberitahu tetapi yg pasti sebelum cuti mid sem..
so kami dah dpt mengagak bila kuiz tersebut akan dijalankan..
mesti pada hari Rabu 12 Ogos...
whatever pn blk ni mesti kne stdy..
so oklah..
nantikan catatan saya yang seterusnya ye...
salam..
maaf sebab lambat update blog ni..
sejujurnya saya tidak begitu berminat untuk kerja-kerja yg perlu di update selalu..
but anyway, saya akan try utk terus mengemaskinikan blog ini..
saya minta maaf byk2 terutama kpd cik azura coz selalu lambat update blog ni..
ini adalah cerita mengenai kelas pada 9 Ogos 2009 iaitu pada hari Ahad..
hari ni kelas masih berjalan seperti biasa dan masih belajar dengan tajuk yg baru..
namun begitu cik azura ada mengingatkan kami untuk bersedia bagi menghadapi kuiz..
tarikhnya tidak diberitahu tetapi yg pasti sebelum cuti mid sem..
so kami dah dpt mengagak bila kuiz tersebut akan dijalankan..
mesti pada hari Rabu 12 Ogos...
whatever pn blk ni mesti kne stdy..
so oklah..
nantikan catatan saya yang seterusnya ye...
salam..
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