Sunday, September 13, 2009

RCA CONNECTION

DEFINITION

An RCA connector, sometimes called cinch plug or lotus plug, is a type of electrical connector that is commonly used in the audio/video market. The name "RCA" derives from the Radio Corporation of America, which introduced the design by the early 1940s to allow mono phonograph players to be connected to amplifiers.

For many other applications it began to replace the older jack plugs used in the audio world when component high fidelity started becoming popular in the 1950s.

The corresponding plug is called an RCA plug or phono plug, for "phonograph". The name "phono plug" is often confused with a "phone plug" which refers to a jack plug or TRS connector.

FUNCTION

In the most normal usage, cables have a standard plug on each end, consisting of a central male connector, surrounded by a ring. The ring is often segmented for flexibility. Devices mount the jack, consisting of a central hole with a ring of metal around it. The ring is slightly smaller in diameter and longer than the ring on the plug, allowing the plug's ring to fit tightly over it. The jack has a small area between the outer and inner rings which is filled with an insulator, typically plastic (very early versions, or those made for use as RF connectors used ceramic).

As with many other connectors, the RCA has been adopted for other uses than originally intended, including as a power connector, an RF connector, and as a connector for loudspeaker cables. Its use as a connector for composite video signals is extremely common, but provides poor impedance matching. RCA connectors and cable are also commonly used to carry S/PDIF-formatted digital audio, with plugs colored orange to differentiate them from other typical connections.

Connections are made by pushing the cable's plug into the female jack on the device. The signal-carrying pin protrudes from the plug, and often comes into contact with the socket before the grounded rings meet, resulting in loud hum or buzz if the audio components are powered while making connections. Continuous noise can occur if the plug partially falls out of the jack, breaking ground connection but not the signal. Some variants of the plug, especially cheaper versions, also give very poor grip and contact between the ground sheaths due to their lack of flexibility.

They are often color-coded, yellow for composite video, red for the right channel, and white or black for the left channel of stereo audio. This trio (or pair) of jacks can be found on the back of almost all audio and video equipment. At least one set is usually found on the front panel of modern TV sets, to facilitate connection of camcorders (through 3.5mm Jack to 3 RCA, also called Mini RCA plug), digital cameras, and video gaming consoles. Although nearly all audio-visual connectors, including audio, composite and component video, and S/PDIF audio can use identical 75 Ω cables, sales of special-purpose cables for each use have proliferated. Varying cable quality means that a cheap line-level audio cable might not successfully transfer component video or digital audio signals due to impedance mismatch and poor shielding quality (causing signal-to-noise ratio to be too low). Cables should meet the S/PDIF specification as defined by the international standard IEC 60958-3 for assured performance.

The male plug has a center pin which is 3.70 mm in diameter, and is surrounded by an outer shell which is 8.25 mm in diameter


Wednesday, September 2, 2009

RazakSAT Satellite

Malaysia’s innovation pride, the RazakSAT satellite, is all set for a lift-off as scheduled on Tuesday from Kwajalein Atoll in the Marshall Islands.

Science, Technology and Innovation Minister Datuk Dr Maximus Ongkili, the ministry’s deputy secretary-general (Policy) Datuk Dr Sharifah Zarah Syed Ahmad and senior officials arrived in Guam today to witness the historical launch via live webcasting, a statement from the Ministry of Science, Technology and Innovation (Mosti) said today.

It said upon arrival, the minister and his delegates were briefed on the readiness of the launch by Astronautic Technology (M) Sdn Bhd chief executive officer Datuk Dr Ahmad Sabirin Arshad.

The minister was also informed that the satellite and launch vehicle, the Falcon 1, which is operated by United States’s Space Exploration Technologies (SpaceX), have now been erected on the launch pad at Omelek Island, the launch site for Falcon 1.

The 180kg remote sensing satellite was designed, developed, built and tested locally and it will also be the first remote sensing satellite to orbit the Equator.

Named after Malaysia’s second prime minister Tun Abdul Razak Hussein, it will orbit the Near Equator Orbit (NEqO) at a nominal altitude of 685km.

The orbital location will allow increased frequency in the image observation of the Earth’s surface and environment.

RazakSAT will carry a high resolution camera which can capture images from space for differnt applications such as precision farming, landscape mapping, disaster mitigation, urban and road network planning, which will not only benefit Malaysia but also other countries along the equatorial region.

The images could also be used to study various meteorological phenomena.

According to the statement, prior to this, the launch if the Low Equatorial Orbit (LEO) satellite was delayed due to vibration problems on the launch vehicle.

However it said all issues related to the problem had been rectified with upgrading carried out by SpaceX.

“I am satisfied with the preparations and necessary steps taken by ATSB and SpaceX to ensure a smooth launch. We hope all Malaysians will pray for the successful launch of RazakSAT,” Ongkili said.

During the visit to Guam, Ongkili and his delegation are also scheduled to visit a marine laboratory and marine heritage and oceanography centre at the University of Guam

Sunday, August 30, 2009

Advantages & Disadvantages Twisted pair, Coaxial cable & Optic fiber

Twisted Pair

Advantages : 1. Cheaper and far easier to splice
2. Less susceptible to electrical interference caused by nearby equipment or wires.
3. In turn are less likely to cause interference themselves.
4. Because it is electrically "cleaner", STP wire can carry data at a faster speed.

Disadvantages : 1. STP wire is that it is physically larger and more expensive than twisted pair
wire.
2. STP is more difficult to connect to a terminating block.

Coaxial Pair

Advantages : 1. Coaxial cable can support greater cable lengths between network devices than twisted pair cable.
2. Thick coaxial cable has an extra protective plastic cover that help keep moisture
away.

Disadvantages : 1. Thick coaxial is that it does not bend easily and is difficult to install.

Fiber Optic

Advantages : 1. One single mode fiber can replace a metal of time larger and heavier.
2. Multi-mode optical cable has a larger diameter and can be used to carry signal
over short distance.

Disadvantages : 1. Fiber optic versus metal cable is that it is difficult to make connections to
fiber optic cable.
2. The optical fiber must be highly polished to allow light to pass with little loss.

Saturday, August 29, 2009

MESH TOPOLOGY & TREE TOPOLOGY

MESH TOPOLOGY

A type of network setup where each of the computers and network devices are interconnected with one another, allowing for most transmission to be distributed even if one of the connections go down. This type of topology is not commonly used for most computer network as it is difficult and expensive to have redundant connection to every computer. However, this type of topology is commonly used for wireless network. Below is a visual example a simple computer setup on a network using a mesh topology.

TREE TOPOLOGY

Among all the network topologies we can derive that 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 school. So that each of the branches can identify the relevant system in their own network and yet connect to the big network in some way.
The tree structure suits best when the network is widely spread and vastly divided into many branches. Like any other topologies, the tree topology has its advantages and disadvantages. A tree network may not suit small networks and it may be a waste of cable to use it for small network. Tree topology has some limitations and the configuration should suit those limitations.

UTP & STP PICTURE/DIAGRAM








UTP_STP_568B_Termination_Standard

Sunday, August 16, 2009

E-COMMERCE

BUSINESS TO BUSINESS

B2B is major portion of E-COMMERCE activities. However, many third party exchanges suffer in making their business succesfull, although the corporations are increasing the adoption of B2B for e-procurement. B2B standars and ebXML are not widely accepted in the real world as we have anticipated.

BUSINESS TO CONSUMER

B2C involves what is known as electronic retailing or e-tailing. E-tailing involves online retail sales. E-tailing makes it easier for a manufacturer to sell directly to a consumer, cutting out the need for an intermediary (retailer). With B2C transactions there is no need for retailers or therefore, no need for a physical store from which to distribute product.

CONSUMER TO CONSUMER

C2C exchange involve all transaction between or among consumers. These transactions can also include third party involvement, usually in the form of those who facilitate the marketplace such as EBay.com.
In C2C network, consumer sell goods and service to another consumers. C2C has given online shopping and trading a new dimension.

Sunday, August 9, 2009

MyEG Portal and Rilek Portal

MyEG PORTAL

MyEG service berhad is concessionaire for the Malaysian E-Goverment MSC Flagship Application. Our role is a service Provider for the E-Services component essentially provides the electronic link between the Goverment and citizens/business.
Through our portal, we offer the Malaysian public a single point of contact between the Goverment and the people it serves. This portal enables Malaysians todynamically interact with numerous agencies within the Federal, State, and the Local Goverment machinery providing services ranging from information searches to license applications.
The cater the services which require physical presence/interaction, MyEG has set up E-Service Centre located throughout the country to complement our online presence. We believe that through this dual approach , we can enhance the relationship and quality of interaction between the Goverment of Malaysia and it's citizens.

RILEK PORTAL

RILEK offers JPJ Driving License service, summons payments and inquiries on Kejara points.
RILEK represent realibiality , simplicity and security. RILEK is eqquiped with high-end multimedia facilities and system support to accomodate heavy traffic low. In addition, it is capable of processing information at an efficientand high-speed rate. RILEK promotes a hasslefree and innovative lifestyle that is designed to eliminate queues and frustrations. RILEK combine advanced technology and human proficiency to enhance your lifestyle. RILEK provide easy transactions electronically via various delivery channels.