Cell phone frequencies are the frequency ranges within the Ultra High Frequency (UHF) band that are designated for cell phone use. Bluetooth devices, wireless networks, and television signals also use this frequency band. Although cellular phone systems divide cities and geographic areas into smaller cells of coverage, it allows for a fair amount of frequency reuse across the network. This ultimlately permits significantly more cell phone users to talk simultaneously on a network. How Are Cell Phone Networks Designed? Typically, a cell phone service provider is assigned up to 832 Read More

The MP3 (Moving Pictures Experts Group) audio file format is compressed in order to allow playback and exchange over the Internet and other size constrained media. Although most audio playback devices and software support the MP3 format, the WAV (Waveform audio) format is uncompressed and capable of storing more detail when further manipulating audio files. A common task that arises for end-users is to convert MP3 to WAV format. The task can be accomplished using online tools or free/low-cost software available from third party vendors. Convert MP3 to WAV Using Read More

Subatomic particles are the most elementary particles found in nature. The three basic subatomic particles that comprise an atom are protons, electrons, and neutrons. The historical definition of a subatomic particle was expanded over the past several decades to include elementary particles that are less complex than an atom and cannot be broken down further. The modern definition of subatomic particles breaks all of them down into either leptons or quarks. Subatomic Particles that Make up an Atom Electron The electron was the first subatomic particle discovered in 1896. U.K. Read More

There are many web browsers available in the market today. Internet Explorer, Mozilla Firefox, Google Chrome, Opera and Apple Safari are few of them which dominate most of the browser market. There are multiple aspects of a web browser on which they can be compared and rated. Before jumping into details, let’s see some statistics of past few years from renowned names in this market. Looking at the below statistical graphs from StatCounter, 2011 was dominated by Internet Explorer. Firefox and Chrome also held major share of the browser market. Read More

A Proctor Test Set is a tool used by telco personnel to diagnose problems with phone lines. You call the Proctor Test Set number and press buttons on a touch tone phone to active the tests you select. For more information, visit the Proctor web page at http://www.proctorinc.com and look at the 51200-S Telephone Test System. What is a Proctor Test Set in my area? If your NPA is not listed try common numbers such as 111 or 117. NPA Telephone Number Geography 805 111 Bakersfield/Santa Barbara, CA 909 117 Read More

HVD (Holographic Versatile Disc) is the next generation in optical disk technology. HVD is still in a research phase that would phenomenally increase the disk storage capacities over the currently existing HD DVD and Blu-ray optical disk systems. According to published statistics, when produced in full scale, HVDs will have a storage capacity of 3.9 terabytes (39,000 GB) and a data transfer rate of 1 GB/s, which is at least six times more than the speed of DVD players. This would, without a doubt, become a giant step in revolutionizing Read More

A Pluggable Authentication Module, or PAM, is a software implementation that allows administrators to significantly change how users log into a server by running a PAM on the server itself. PAMs are used to provide authentication of users as well as perform any tasks that are associated with initializing or terminating the session, such as logging a user into the server, displaying a personalized webpage, and logging the user out of the server when he/she is finished.   How Pluggable Authentication Modules Work PAMs can be embedded into existing servers Read More

Registered memory modules have built-in registers on their address and control lines. A register is a very small temporary holding area (usually 64 bits) for data. These registers act as buffers between the CPU and the memory. The use of registered memory increases system reliability, but also slows the system down a very slight bit as data must be moved through the registers. Some systems do not support registered memory, others require registered memory, and many more give you the option to use registered or unregistered memory. The use of Read More

`Sudo` is an enhanced alternative to the Unix `su` command. Sudo stands for “su do,” and means “do something as the supervisor.” Sudo’s Capabilities Sudo allows system administrators to control who can run some (or all) commands as root. This ability to restrict users can be configured on a per-host basis, and is a much more flexible way of controlling what commands a user may perform. Sudo allows users to perform certain, selected commands as if they were the UNIX root account, but because Sudo is customizable to give selective Read More

Duplex simply means that the communications device enables users to talk to someone in another location and the person in the other location to respond to the user via the same type of device. As an example, when someone makes a telephone call, he/she is engaging in a duplex procedure. The same is true when voice to voice communication is done via a computer. Examples of Half Duplex Devices and How They Work In contrast, a half duplex enables only one party to speak at a time. The best example Read More