May, 2008

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Amplifier A device used to boost the strength of an electronic signal.

Amplitude Modulation (AM) Amplitude Modulation is a process of varying the amplitude (height of the carrier wave) of the carrier signal in accordance with the information to be transmitted.

Analog A form of transmitting information characterized by continuously variable quantities, as opposed to digital transmission, which is characterized by discrete bits of information in numerical steps. An analog signal is responsive to changes in light, sound, heat and pressure.

Analog-to-Digital Conversion (ADC) Process of converting analog signals to a digital representation. DAC represents the reverse translation. Antenna Device used for sending or receiving electromagnetic waves. Depending on their use and operating frequency, antennas can take the form of a single piece of wire, a di-pole a grid such as a yagi array, a horn, a helix, a sophisticated parabolic-shaped dish, or a phase array of active electronic elements of virtually any flat or convoluted surface.

Aperture A cross sectional area of the antenna which is exposed to the satellite signal.

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MRTG is a powerful tool used for monitoring the traffic load on network links(router,switch…).In other word , it is a web based application used to monitor and graphically display traffic and usage or information of a device. It generates HTML pages containing PNG images with visual representation of the traffic. It can produce daily, weekly, monthly, and yearly graphs. In addition to monitoring , it can also generate graphs based on the output of any application, for example, SIGNAL STRENGTH of a modem(Eb/No), Voltage level of UPS(input /output), memory usage etc. MRTG is written in perl and works on most of the operating systems ,including most Microsoft Windows versions,UNIX/Linux. (more…)

This article will teach you how to use and configure a Cisco 26xx router series. The commands here in this article will work with almost all the cisco router. In short, this article is for the beginners only! For more details please refer to Cisco’s web site.

Operation Modes

The Cisco Software provides access to four different operation modes. Each command mode provides a different group of related commands. For security reasons, the Cisco IOS software provides two levels of access to commands: user and privileged. The unprivileged user mode is called user EXEC mode. The privileged mode is called privileged EXEC mode and requires a password. (more…)