Virtual Carrier Sensing and Network Allocation vector

Carrier sensing is used to determine if the medium is available. In addition to the physical carrier sensing, 802.11 employs also virtual carrier sensing functions. If either one of them indicates that the medium is busy, the station defers the transmission. Virtual carrier sensing is provided by the network allocation vector, Most 802.11 frames carry a duration field, which can be used to reserve the medium for a fixed time period. Stations set the NAV to the time for which they expect to use the medium including any frames necessary to complete the current operation. Other stations that receive the frame set their NAV timer which is a timer that indicates the amount of time the medium will be reserved and count down from the NAV to 0. Read More

The Optical Fiber and Fiber cables

The manufacture and construction of the basic fiber are somewhat complicated. In simple terms, a highly refined quartz tube that will eventually be filled with a combination of gases is selected to start the process. This tube, about 4 ft long and about 1 inc in diameter, is placed in a lathe and the gases are injected into the hollow tube. The tube is rotated over a flame and subjected to temperatures of about 1600 degree F. These fiber cables are made with many materials. Read More

Why we used Optical Fiber?

We used optical fiber technology because of rapidly increasing demands for telephone communication throughout the world, multi-conductor copper cables have become not only very expensive but also an inefficient way to meet these information requirements. The frequency limitations inherent in the copper conductor system make a conducting medium for high speed communications necessary. Read More

Characteristics of Switching System

When you discuss about the characteristics of switching system it’s different from each other. Circuit switching has one kind of rule and on the other hand packet switching plays another rule. Like circuit switching need 64 Kbps channel for voice transmission on the other side packet switching don’t have any limit. Read More     

Switching in a Tele-communications system

Switching is the best generic method of establishment a path for point to point communication in a network. It is used in telecommunication system. There are two types of switching system we have these are as follows: a. Circuit Switching b. Packet switching. ReadMore

Free PC error Software Download

Someone can be thinking about his personal computer software problems. A computer user has to face some software problems when adding or removing some programs in his computer. Attempting to clean up the registry manually can lead to worse problems. If someone fall into this sort of problems at first they go to the software store and try to solve this. But today you can find all kinds of software which you need for your PC in the internet and can download it free. But when download the software must read up on several different titles and understand their features because there are so many titles out there. Read More    

Fading in the mobile environment

Fading is very important in the communication system. There are different kinds of fading technique for avoiding these kinds of communication problems. The term fading refers to the time variation of received signal power caused by changes in the transmission medium or paths. Read More

How can you running your Laptop fast?

If your Laptop is not running fast and it has a problem when it boot and when you are working in too many program. There is a lot of factors for the system making slow. It is not an easy task to keep a computer running fast. For this you have to know lots of things about technical knowledge. When you running too many programs in your computer at that time 90% of your RAM is being used and we knew that your RAM is not unlimited. In that case the system became slow, so for avoiding these problems you can increase your RAM or uninstalled your some program. Another important thing is you had to install a better anti virus, because of using the internet some Mala-wares, Viruses and Spy-ware are attack in your Laptop and making some damage. Read More. 

Upgrade version Laptop Technology

Now a days Laptop became the most workable and more powerful computer, Most of the people used this latest computer because they can easily carry it anywhere they want and also they can used it as like as their personal computer. Laptop and notebook computer technology is advancing a high speed. There is a lot of upcoming laptop and notebook computer technologies are ready for changing their structure. Some of them are like 64 Bit Laptops, Dual Core Notebooks etc. 

The museum security system.

The museum security system is very important for the museum as well as for the nations for collecting their historical things. For the security of a museum at first people take some anti- air defense. It is very necessary for a nation to protect their historical, scientific, cultural and artistic resource. In recent time modern communications system used for the museum security for upgrading the system. This types of technology like   active infrared, passive infrared, microwave, ultrasound, voice and other anti-theft Detector to form a variety of detection means of anti-theft alarm system, burglar alarm to a new level of technology, fire alarm, television monitor, the Security and Protection System etc. Read more