Fisco's Tech

Types and Characteristics of WANs

What is a WAN?

There are two prevailing definitions of a Wide Area Network (WAN). The book definition of a WAN is a network that spans large geographical locations, usually to interconnect multiple Local Area Networks (LANs). The practical definition of a WAN is a network that traverses a public network or commercial carrier, using one of several WAN technologies

What are its Main Components?

The main components for a WAN are routers, switches and modems. These components are described below in the hardware section.

CPE - Devices on the subscriber premises are called customer premises equipment (CPE).
The subscriber owns the CPE or leases the CPE from the service provider. A copper or fiber cable connects the CPE to the service provider's nearest exchange or central office. This cabling is often called the local loop, or "last-mile".

DTE/DCE - Devices that put data on the local loop are called data circuit-terminating equipment, or data communications equipment (DCE). The customer devices that pass the data to the DCE are called data terminal equipment (DTE). The DCE primarily provides an interface for the DTE into the communication link on the WAN cloud.

Hardware

In a WAN you will need various types of hardware components for it to function. The typical items of hardware that you will need in a WAN are:

Router - An electronic device that connects a local area network (LAN) to a wide area network (WAN) and handles the task of routing messages between the two networks. Operates at layer 3, and makes decisions using IP addresses.

Switch - A switch is a network device that selects a path or circuit for sending a unit of data to its next destination. Operates at layer 2, and uses MAC addresses to send data to correct destination.

Modem - Short for modulator/demodulator, a modem enables a computer to communicate with other computers over telephone lines. Operates at layer 1, where signals are converted from digital to analogue and vice versa for transmission and receiving.

Wan Standards

WANs operate within the OSI model using layer 1 and layer 2 levels. The data link layer and the physical layer. The physical layer protocols describe how to provide electrical, mechanical and functional connections to the services provided by the ISP. The data link layer defines how data is encapsulated for transmission to remote sites.

Encapsulation

Encapsulation is the wrapping of data in a particular protocol header. Remember that WANs operate at the physical layer and the data link layer of the osi model and that higher layer protocols such as IP are encapsulated when sent across the WAN link. Serial interfaces support a wide range of WAN encapsulation types, which must be manually specified. These types include SDLC, PPP, Frame delay etc. Regardless of WAN encapsulation used it must be identical on both sides of the point to point link.

Packet and Circuit Switching

Circuit switching and packet switching are both used in high-capacity networks.
The majority of switched networks today get data across the network
through packet switching.

Circuit-switching is more reliable than packet-switching. Circuit switching is old and expensive, packet switching is more modern.

General Routing Issues

What is a Routing Protocol?

A routing protocol is a protocol that specifies how routers communicate and exchange information on a network. Each router has prior knowledge of its immediate neighbours and knows the structure of the network topology. The routers know this because the routing protocol shares this information.

Protocol

RIP (Routing Information Protocol) was one of the most commonly uses protocols on internal networks. Routers use RIP to dynamically adapt changes to the network connections and communicate information about which networks routers can reach and the distance between them. RIP is sometimes said to stand for Rest in Pieces in reference to the reputation that RIP has for breaking unexpectedly and rendering a network unable to function.

Routing Algorithms

Distance Vector

This type of routing protocol requires that each router simply inform its neighbours of its routing table. The distance vector protocol is also known as the bellman-ford algorithm.

Link State

This type of routing protocol requires that each router maintain a partial map of the network. The link state algorithm is also know as Dijkstra's algorithm.

IGRP

IGRP is a type of distance vector routing protocol invented by cisco used to exchange routing data in a autonomous system. Distance vector protocols measure distances and compare routes. Routers that use distance vector must send all or a portion of their routing table in a routing update message at regular intervals to each neighbour router.

Addressing and Routing

What does routing mean?

Routing is the process of deciding how to move packets from one network to another.
The directions also known as routes can be learned by a router using a routing protocol then the information is passed from router to router along the route of the destination.

IP Address's

Every machine connected to the internet is assigned an IP address. An example of an IP address would be 192.168.0.1. IP addresses are displayed in decimal format to make it easier for humans to understand but computers communicate in binary form. The four numbers that separate an IP address are called Octets. Each position consists of eight bits. When added to together you get 32 bit address. The purpose of each octet in an IP address is to create classes of IP addresses that can be assigned within a network. There are three main classes that we deal with Class A, B and C. The octets of an IP address are split into two parts Network and Host. In a class A address the first octet is the network portion, this determines which network the computer belongs to, the last octets of the address are the hosts that belong to the network.

Sub netting

Sub netting allows you to create multiple networks within a class A, B or C address. The subnet address is the address used by your LAN. In a Class C network address you would have a subnet mask of 255.255.255.0. A subnet mask identifies which portion is network and which is host. For example 192.168.6.15 the first octet three octets are the Network address and the last octet being the host(Workstation). It is important to subnet a network because gateways need to forward packets to other LANS. By giving each NIC on the gateway an IP address and a Subnet mask it allows the gateways to route packets from LAN to LAN. Once the packet arrives at its destination, the gateway then uses the bits of the subnet portion of the IP address to decide which LAN to send the packets.

Circuit Switched Leased Lines

A circuit switched network is one that establishes a dedicated circuit (or channel) between nodes and terminals before the users may communicate. Here are some terminologies associated with a Circuit switched network.

Frame relay is a telecommunication service designed for cost-efficient data transmission between local area networks (LANs)

Basic rate interference is a service used by small business for internet connectivity. An ISDN BRI provides two 64 Kbps digital channels to the user.
Primary rate interface (PRI) is a telecommunications standard for carrying voice and data transmissions between two locations
All data and voice channels are ISDN and operate at 64kbit/s

Packet Switching

http://www.raduniversity.com/networks/2004/PacketSwitching/main.htm - _Toc80455261

Packet switching refers to protocols in which messages are broken up into small packets before they are sent. Each packet is then transmitted over the Internet. At the destination the packets are reassembled into the original message. Packet switching main difference from Circuit Switching is that that the communication lines are not dedicated to passing messages from the source to the destination. In Packet Switching, different messages can use the same network resources within the same time period.

http://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode

Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and protocolwhich encodes data into small fixed-sized cells.

ISDN is used to carry voice, data, video and images across a telephone network. ISDN stands for integrated services Digital Network. Isdn also provides users with a 128kbps bandwidth. This is done through frame relay. Frame relay complements and provides a service between ISDN, which offers bandwidth at 128 Kbps and Asynchronous Transfer Mode which operates in somewhat similar fashion to frame relay but at speeds from 155.520 Mbps or 622.080 Mbps. Frame relay is based on the older X.25 packet switching technology and is used to transmit analogue signals such as telephone conversations.

PSDN stands for packet switched data network and is a data communication network. Packet switched networks do not establish a physical communication signal like the public telephone does (circuit switched network) Packets are sent on a fixed length basis and assigned with a source and a destination address. The packets then rely on the routers to read the address and route the packets through the network.

Mobile and Broadband Services

Digital Subscriber line(DSL) is mainly used to bring high bandwidth connections to homes and small business's over a copper wire telephone line. This is can only be achieved if you stay within the range of the telephone exchange. DSL offers download rates of up to 6mbps allowing continuous transmission of video, audio and 3D effects. DSL is set to replace ISDN and compete with the cable modem in providing multimedia to homes. DSL works by connecting your telephone line to the telephone office over copper wires that are twisted together.

Asymmetric Digital Subscribers Line is most commonly used for home users. It provides a high download speed but a lower upload speed. Using ADSL, up to 6.1 megabits per second of data can be sent downstream and up to 640 Kbps upstream.

http://en.wikipedia.org/wiki/Symmetric_Digital_Subscriber_Line

Symmetric Digital Subscriber Line is a digital subcriber line which runs over one pair of copper wires. The main difference between ADSL and SDSL is the difference in upload and download speeds. SDSL allows the same upstream data rate and downstream data rate as ADSL upstream can be very slow.

http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci558545,00.html

HDSL High bit-rate Digital Subscriber Line, one of the earliest forms of DSL, is used for wideband digital transmission within a corporate site and between the telephone company and a customer. The main characteristic of HDSL is that provides equal bandwidth in both directions.

IDSL is a system in which data is transmitted at 128 Kbps on a regular copper telephone line from a user to a destination using digital transmission.

The Local Loop enables operators to connect directly to the consumer via copper local loops and then add their own equipment to offer broadband and other services. This process involves operators accessing local exchange buildings to connect to a network of copper lines which connect them to homes and businesses. BT is an Example of a Local Exchange. The local loop connecting the telephone exchange to most subscribers is capable of carrying frequencies well beyond the 3.4 kHz upper limit.

Benefits of using DSL

DSL can provide virtually instantaneous transmission of voice, data and video over ordinary copper phone lines. A DSL connection can eliminate delays when waiting to download information and graphics from the Internet. It provides users with a cost effective high speed Internet connection. Another benefit is that a DSL connection is always on-line (like a LAN connection) with no waiting time for dialling or connecting.

There are now more than 10 million broadband connections in the UK. By December 2005 there were 9.792 million broadband connections in the UK and the average broadband take up rate during the three months to December was more than 70,000 per week.

By Jake B

No that's not a typo, Its real. A new gadget now allows you to make unlimited calling to anywhere in the US and Canada for $20 a year, That's about a buck and a half per month. That's incredible. This revolutionary piece of equipment allows this, It's called the MagicJack. It's really simple. Their are only 3 things required. A home phone, The MagicJack and broadband internet service.

MagicJack

How this works:

This thing couldn't be easier to use, You plug it into your windows computer USB port. The software takes about 30 seconds to load (First time use requires brief account activation). Plug your homephone line into the MagicJack and your ready to go. The call quality is good, It's not as good as a regular landline but for the price you really cant go wrong. Think about it, For what your probably paying for a month's worth of service you could use that for a whole year using this. The only downside I can see for this is that you must have your computer plugged in and running to be able to make and receive calls. This is a small price to pay though for UNLIMITED local and long distance calling.

I am in no way affiliated with this product, I own one myself though and it's amazing. I recommend everyone picking one of these up, It costs $40 and the first year of service is free. ($20 after that)

Check out the MagicJack official website by clicking the following link.
http://www.magicjack.com/6/index.asp

By Colin Yao

When testing loss in a fiber optic link, some basic principles must be kept in mind all the time.

1.The testing wavelength should always be the same as the working wavelength. Because optical fiber loss varies with light wavelength, you will get incorrect result if your measuring wavelength is different from the actual working wavelength. For example, if a system is designed for 1550nm but you test it with 1310nm light source and power meter, the result will not be correct.

2.The testing light source should be the same as the intended working lightwave equipment light source. If the system is designed for a LED source, you should test it with a LED source. If the system is designed for multimode laser light, you should use a multimode laser light source for testing. This is also true for single mode laser light source.

Fiber optic equipment used in a loss testing

In a basic loss testing setup, four types of test equipment are needed. They are the light source, the power meter, the reference patch cables and the adapter (mating sleeve).

Here are some considerations when choosing your equipment.

The light source should have the same wavelength as the operating equipment, proper mode (multimode or single mode, should be same as the operating equipment), type (LED or laser, same as the operating equipment) and proper connector.

The power meter should have the same wavelength as the light source, proper connector and calibrated.

The reference patch cables should be high quality with know loss, proper connectors and be the same type as the fiber plant being tested.

The adapter (mating sleeve) should be with high quality ceramic sleeves and be proper type (FC, SC, LC, etc).

Understanding dB (decibel) in fiber optic loss testing

As in any power measurement, fiber optic light power measurement unit can be expressed in milliwatt (mW), but a more convenient unit is dB(decibel).

Decibel (dB) is most often used in electronics testing. It is the ratio between two levels. One level is the input and the other level is the output. The ratio is calculated in logarithmic as explained below.

For power measurement, dB is defined as: dB = 10 x log(output power/input power)

So for example, after a fiber link, the output light power level becomes 50% of its input, the loss of the link will be 10log(0.5)= -3 dB.

Since dB is actually a ratio, it has no absolute units. So from above measurement sample, we have no idea of the actual power, may it be 0.1 mW or 1 mW.

That is why we have another unit dBm. It is the ratio of the measured power to 1mW of reference power. It is defined as: dBm = 10xlog(measured power/1mW)

So for example, a 0.1mW light power expressed in dBm will be 10xlog(0.1mW/1mW)=-10 dBm.

From above we know that dBm is a absolute unit, we know exactly how many mW it is.

For fiber optic loss testing, decibel is the most often used unit since it is much easier to work with. Why? Because two dB values can be simply added or subtracted. For example, a total fiber link may have three sections, each has loss of 0.5dB, 5dB and 0.5dB. The total loss can then be easily concluded as 0.5dB + 5dB + 0.5dB = 6 dB. You can try to convert it to actual milliwatt and you will see that I am right!

By Colin Wolfenden

Most people might think of screensavers as just a bunch of animated scenes or beautiful pictures sitting on their PC desktop. A screen saver is far more however. You may be surprised to learn that behind the scenes a screensaver is helping you in more ways than one, such as:

Stress Buster

With many of the relaxing screensaver themes available today, simply watching can reduce your stress levels significantly. In particular, many of the nature screen savers which include sounds can be an escape from today's hectic pace and noise.

Monitor Protection

Screensavers help protect your computer screen from image burn. When the same image is displayed on the screen for a long period it can burn permanently into the screen. This was the original reason for screensaver development. Although screen burn is not as much of a problem these days, some of the new LCD screens can still be affected by it. Having a nice screen saver will give you added protection just to make sure.

You may realize by now that downloading a screensaver for your desktop is a good idea; which it is. However, there are a few things to consider. Because a screensaver is typically an executable file, there are risks you should be aware of, namely spyware, viruses and trojans. All these little nasties can be packaged into the screen saver file and infect your computer when you install it.

Choosing a Safe Screensaver

The best way to protect your PC from spyware and viruses is to follow these simple steps:

1) Image Quality

Does the preview screensaver have high quality images or animations? While this is not always true, in general high quality animations or images are more likely to be produced by a genuine business.

2) Website Address

You may find screensaver download banners and links on a wide variety of websites. However, take note of the website where you are taken to for the download. For instance you may click on a banner on a web page which takes you to the main screensaver download site. If the download site looks unprofessional or has a dodgy web address then it could be risky to download any of their files.

3) Guarantees

Most of the better quality screensaver download sites will prominently display some sort of virus and spyware guarantee. While you can't solely rely on this it is a good general guide when choosing a screensaver download site.

By using the three points above together you stand the best chance of protecting your system from viruses and spyware when downloading screensavers. The reason that screensavers where originally developed is not as much of a problem today as it was. However, as with many things, they have evolved to have other purposes. Grab yourself a nice screensaver today and de-stress, enjoy the show, and be happy.

By Mike Selvon

The world of digital video editing has been opened up to regular people, instead of specialized video editors, thanks to the world of computers and camcorders. For years, a person who wanted to make one large video from their collection would have to have gone to a professional editor. Thanks to the technology of today, a person can now edit their own videos with the right equipment, which is readily available as long as a person knows what they are looking for in editing software.

The first of the components to making great digital video editing possible is a camcorder with certain features. A person should look for a model that has optical stabilization, which is an option that keeps the image from appearing shaky.

This occurs inside the camera automatically and is a feature that only the higher end models have. For editing purposes, a person will definitely want a camcorder that supports FireWire input and output. If the machine does not have this, then a person is wasting their money and time.

The other main tool that will be needed for editing is a computer. In order to create great videos, the computer needs at least thirty gigs of space available. This will allow a person to create a video that lasts approximately one hour. Also needed will be an eight meg graphics card. Otherwise, the video quality will be dull.

Even the new Macs will be able to create great videos as long as a G4 is present. All a person will need for either a Mac or PC is the right video editing software, such as Adobe Premiere Elements 4 or Pinnacle Studio Ultimate 11, to name only two of the many choices available.

Digital video editing is one arena in which most people have yet to indulge. However, with the right tools, anyone can take part in editing their own home movies. No matter if a person invests in a handycam or a Samsung digital camcorder, the fact that they are taking part in capturing their memories for future generations can prove to be an important aspect of a their life.

By Mohita Bhargava

Computer Paper is used to describe any paper that can aptly used with computer printers. Some of the different types of Computer Papers one can get in the market are for laser, inkjet , and photo . Basically the printer paper is available in two finishes: matte and glossy. Besides these there are continuous sheets of papers also available and are used in dot matrix printers. It can be completely white or have green strips that assist in easy reading of text in one go. The dot matrix printing papers are available in two formats : single-part and multi-part.

Selecting good quality Computer Paper is not an easy task. There are a number of companies that offer them in different types for meeting your official and personal needs. With the computer becoming a necessity, people look for the right one that meets their needs. For making a good impression on your business partners, for making presentations, for making school projects for kids, Computer Paper is essential in aspects.

Computer Paper has the following properties that will help you in choosing the right type for yourself.

Weight: For daily use Standard 20# paper is used. It is used for making eye catching presentations within or outside the companies. It can be used for applications where quality is important. Usually it is said that the higher the quality of paper the more durable it will. Further it will gives pretty good substantial feel.

Brightness: The computer papers have a brightness rating between 80 to 100. The higher the number chosen for white paper the brighter it will be. There are different types of colored paper also. Hence, check for the sample print before buying. There is special photo paper, greeting card paper and other specialty papers available. If you are planning to print some images or planning to start your own publication, then go in for a heavier paper with extra brightness.

Opacity: Some papers prevent light from passing through, like the ones used for making invitation cards, or visiting cards. The standard paper is translucent, hence go for the heavier one as it gets opaque.

Smoothness: Depending on one's needs, one must choose the paper. The texture of paper to be used gets different with the application. Inkjet Computer Paper allows the ink to dry faster and produce sharper output.

These are some factors that will enable you to choose the right Computer Paper for your project. For more information visit GoToForms.com

By Dave Talbot

Technology never seems to stop racing ahead and before one product has even gone to market quite often it has been superseded by a newer faster model.

Technology geeks (I can say that because I am one myself) go out and buy the latest gadgets at the highest prices because they all have some new fangled function or a re sporting the latest colors or designs when they haven't really used all the functionality of the one they already own.

When it comes to the family Pc however I think the technology giants like Intel, Amd, Hp and Dell for example are all missing the point when it comes to your average consumer.

A majority of computer users do not play games on their computers (they probably have a play station or a Wii), nor do they use massively processor hungry applications like computer aided design packages or finite element (fea) calculation packages.

If we listen to all the advertising blurb that computer vendors and suppliers seem happy to ply us with, we would all believe we need multiple core machines , but reality couldn't be further from the truth.

And if the processor manufacturers were entirely, open they would also tell you that there are still today very few programs that can even take advantage of the multithreaded capability of today's breed of processors.

The truth of the matter is that Pc technology and power is far outreaching the users real needs, lets face it, you probably have more raw processing capability sat in the average home than they had to send man into space in the early days!

One fact that is undeniable though is that when you go and buy your next Pc with all its raw computing power you will probably still need to by something extra to make it work efficiently within a short space of time.

A well rounded and efficient computer or laptop isn't just about the processor speed, granted that does help but only up to a point. A good analogy would be why buy a sports car that is capable of over a hundred and fifty miles and hour when the most you will ever do is 90?

Equally , with your average car a good all round performer will be the sum of all its components , tires, suspension etc. not just the power of the engine. But what good is a 150 mph engine if the tires are only rated for 70mph.

The same thing will apply to the common Pc, but where there are consumer laws governing the sale of automobiles the same level of strictness does not apply to computers . And quite often what you buy may not be quite up to the job.

Of course, what we are referring to is the amount of computer memory in your laptop or Pc.

As Pc power increases programs get more complex, and as they get more complex they use more computer memory.

The more programs you install even if only working in the background i.e. anti virus programs, music programs and system utilities the more memory is used and so on.

Simply put the more memory the programs have to access, the faster and more efficiently the Pc will work.

This is all well and good but the problem occurs when your computer runs out of memory and has to start using the hard drive as extended memory instead.

This is magnitudes slower performance wise than the system memory and will not stop your Pc from working but will certainly slow it down, sometimes to the point of almost stopping.

It's a bit like putting a block of wood under your cars gas pedal, it will still accelerate but just not as quickly as it is really capable of.

Budget driven customers often rely on the advice of the Pc reseller but quite often they are more interested in making a quick sale than giving sound advice.

After all lets face it, a little additional memory should not cost more than $50 - $100 extra and is a worthy investment if you plan to keep your hardware for more than a year, or have more than a handful of programs you want to load up.

Are computer resellers all to blame though? Expert opinion would say not , the computer manufactures should set a minimum level of memory in new systems given that they are well aware that budget machines memory levels are arguably barely adequate.

The positive side to all this is of course that there is a massive market in after sales computer memory which seems to grow ever stronger because of the need for more memory in a machine.

Computer memory upgrades are easily obtainable fortunately and something which you can do yourself. You can do an online memory scan to ensure and guarantee that the memory is indeed correct for your system and fit it yourself when it arrives a few days later if ordered on line.

Or you can contact you local computer repair professional who can also perform this inexpensive task if you have already purchased a new Pc or if your existing system is running slowly.

If you are thinking of purchasing new hardware then do yourself a favor and make sure you get a memory upgrade if you are purchasing a budget machine. If the salesperson does not give you the option ask for it. You will be the person that benefits in the long run.

By Ramakrishna Thinnavelli

Spyware is one of the biggest threats to your privacy and the security
of your data. It's also the number one cause of system slowdowns on computers
because it uses precious system resources including RAM (memory) and
hard drive space.

Some Symptoms of Spyware, Adware, Malware Infection:
The symptoms of a malware infection vary. Your web browsing speed may be slow. Your computer, in general, may be slower that it was and may take much longer to start up than
it used to.

It is likely Internet Explorer is modified. You homepage and/or search
page may be changed, new favorites that you didn't create may appear,
a new toolbar may appear or you may end up at unknown web sites when
you try to do a search.

To prevent you from undoing the browser modifications made by a
malware program, some of them remove or disable the Internet Options
from the Tools Menu and from the Control Panel. If you try to reset
your home page and can't, it's likely due to malware. If you can't
get to anti-virus or security web sites, but can get to other web sites,
it's likely due to malware.

Adware will bombard you with pop-up ads. More malicious programs serve
up a constant barrage of ads for pornographic web sites. That's on top

of the pop-ups from the web sites you're viewing. If you see pop-up
ads even when you are offline, it's due to malware.

Actual Spyware (as opposed to other malware) has to phone home to
report what it found. If your firewall provides outbound protection
you may see the 'phone call' and be able to stop it.

Malicious software may also shut down or disable your anti-virus
program or your firewall program. It may prevent the normal activity
of your anti-Spyware software. It may prevent you from accessing
Task Manager or msconfig or regedit.

Adware programs may create new icons on the Windows desktop,
task bar, or system tray. They may also create popup windows that you
are unable to close. If your computer mysteriously dials the phone on
its own, it may be infected with a porn dialing program.
Click here for free top rated anti spyware.

By Max Penn Junior

A remote keylogger can be the thing to unlocking a load of valuable information that until now has been a mystery to you. Keyloggers are very popular and have a wide range of applications today. They are used to record what is typed on a keyboard throughout its usage. Some devices can also record the time that something was typed, the program it was typed into, and even alert you to specific keywords being used. So what are some of the various uses for this product?

• Law enforcement can use a remote keylogger to find the password of hidden, criminal programs,
information and documents. Many major cases have been solved in this fashion!

• Learning about the correct application and design of software and programs. You can see if people
use your computer program correctly by what they are typing as they are using it.

• Checking in on your employees to see if they are being productive or using your computer for
personal, illicit or illegal projects.

• Monitoring your spouse to see if they are in a secret affair.

• Protecting your children from online predators.

Once you know what you want to find out from a keylogger, you have to be informed and know about all of the different models you can find. It can work via one of two methods; either software or hardware.

In software form, it comes into the form of actual software programs that are loaded onto the computer that you want to monitor. A file is then created which logs all of the keystrokes. A remote software keylogger sends that file to another computer so you can view it without ever being there. You can also install it without ever touching that computer, attaching it to another program and sending it through email.

While some such software run completely undetected, one downside is some software programs can be found out about by the user. Additionally, such software often have the capability of sending screenshots of what is going on, as well as keyword alerts to specific things such as "porn" or "sex".

Hardware key loggers are physical devices that are either connected to or implanted into the keyboard itself. While these can't be detected through the computer system, because they aren't actually in it, a suspicious person could explore and find the keylogging device. Hardware models do not have additional features such as the screenshot capability.

So a remote keylogger can be either software or hardware based. As mentioned, software solutions can be sent and installed through email and then monitored in a different location. Hardware solutions still need to be physically installed but they can be controlled and watched from someplace else. There are also different ways you can retrieve the important logs. They can be uploaded to a website or ftp account where you can view or download them, they can be sent to an email address or it can be even be wirelessly transmitted.

There are many different applications for these devices and many different devices to choose from. Don't leave yourself wondering if your spouse is cheating, your child is in danger or your coworker is abusing your equipment, time and money! For most people, a remote keylogger that can run undetected provides the best combination of desired results, ease of use and the stealthy obtainment of information.

By : Nick Nguyen

High speed flash cards, high capacities and only three major companies have them. 300x compact flash cards are the fastest in the market but there are not many who make them. The cream of the crop can be found in this article.

The Transcend Extreme Speed 300x CompactFlash card is one of the fastest available in the market. It is designed specifically for professional photographers but the CF card can be used with anything that is compatible with it. Since it supports Ultra DMA mode operation, it can support very fast transfer speeds of up to 45MB/s. DMA stands for Direct Memory Access which allows the CPU to operate more than one function at a time during data transferring. In a sense, having Ultra DMA would speed up the flash drive because the CPU doesn't have to copy each piece of data from the source to the destination.

So far, there are only 3 major companies that have released these high speed flash cards which are Lexar, Transcend, and Sony where Transcend is the only one that offers a 16GB capacity. Supposedly, all of them can transfer as fast as 45MB/s which are why these CF cards are so expensive. Transcend's flash card sticks out mostly due to the fact that it has an advanced Error Correction Code which correct errors during data transfer automatically. With that function in place, you don't have to worry about the integrity of the pictures that you take. However, you may have to use a third party image recovery software if your card happens to stop functioning.

Lexar's compact flash card includes Lexar Image Rescue 3, which is an image recovery software, when you purchase it from them. I don't know how well it performs but to have this is a short sigh of relief for most consumers because sometimes they might forget to back up their images and lose all their data. Although it includes the software, it shouldn't mean that you should not back your files but it provides a mean of recovery just in case something does happen. Sony also provides support when it comes to image recovery; however, you have to send it back to them to recover the images for you.

Overall, the performance of the compact flash cards is very similar to each other. What make these different from each other are the services that come with the product. I still think Transcend's 300x CF card would be a great choice because of the price. Currently, Lexar is selling the 8GB for $199 but Transcend sells their 16GB for $218.99. You can find it at shop.transcendusa.com for that low price. Each of these companies have been established long enough to have credibility so, you should not worry about the quality of the product. It is entirely up to you to see which one is the best option.