Warning! This article contains graphic descriptions. The readers may experience anxiety, confusion, or a burning desire to “start working immediately”. Professional guidance it is strongly advised!

Unfortunately, it is sufficient to see the name of the beast, dsPIC30F4011, and many readers are going to shy away, or even burst into tears. No, dear friends, there is nothing to fear, and I intend to present how you could easily tame this terrifying dsPIC30F40111 monster and put it to work for you, into many beneficial applications.

Now, the first thing you need to do is to capture the beast. For this, you have to take the jungle path–also known as the “Internet”. Walk up to the monsters’ lair, Microchip®, and there you could capture, or purchase one dsPIC30F4011 animal for about 12 pieces of silver.

Once you bring your wild creature home, analyze its shape and, mostly, its behavior. You will see the beast looks like any ordinary monster IC of the DIP40 type, and this is good news, because it is best to use through-hole IC type of beasts, during hardware/firmware development work–some of them could pass away while experimenting, so… You think, probably, the 40 legs the monster has are not sufficient for your particular tasks. Do not worry about this, because you are going to discover means to multiply monster’s legs to hundreds of them, just like the truly ferocious monsters! Well, this is all about the shape of the beast, and you can see there is nothing impressive about it. However, you also need to study monster’s behavior; this time a bit more careful.

Please be aware there are thorough treaties–also known as “Data Sheets”–where the dsPIC30F4011 behavior it is described in details, and I will only point out few of the most terrifying features. First, our monster has Flash memory, about 48 Kbytes, and this is very good, because we can erase sucker’s memory whenever it goes nuts, or when we want to teach it new tricks. Next, our monster has 1 Kbytes permanent memory of type EEPROM, and this allows us to store there various configuration data, or to work with adaptive-learning firmware routines. The presence of this EEPROM memory tells us, in fact, our monster is of good quality!

Now, the most terrifying aspect is, our monster belongs to the 16 bits family, but my advice is to ignore this. Handling 8, 16, or 32 bits monsters it is all the same; the only significant difference is in the tools we use to tame the beast. Another shocking feature you are going to discover sooner or later is, our monster belongs to the ferocious dsPIC® family, hence it is capable of DSP (Digital Signal Processing–please read my articles about this) and of very fast mathematical calculations. This is, again, very good news, because we need both fast and very intelligent microcontroller-creatures. Regarding its reflexes, our monster works at either 20 or 30 MIPS (Mega Instructions per Second), which should be fair enough for most demanding applications. In order to feed it properly, you should know this animal likes only regulated DC voltage of 2.5 V up to 5 V.

Our 40-legs creature is capable of UART, SPI, CAN, and I2C communications. In addition, it has 6 PWM channels, because it appears it has been specifically bred for motor control applications–ugh, scary! The beauty is, it also has ICSP (In Circuit Serial Programming), and this allows us to do many annoying and nasty things to it. Ha, ha!

What else… Ah! Nine of those ugly crooked legs are capable of 10 bits Analog-to-Digital conversion at maximum 0.5 Msps (Mega samples per second); then, about 30 legs are capable of general I/O, and 3 of them are also external interrupts. Wow, the Interrupts! Here is where the power of the monster actually lies! The dsPIC30F4011 beast has no more and no less than 30 interrupt sources, with 8 selectable priority levels.

Fact is, we could go on and on, but it is better to keep it short; besides, I would like you to discover few interesting things for yourself. Now, it seems our monster promises a lot, but the problem is: “How do we tame it?” Unfortunately, we cannot use the good, long-time tested methods of fire, hunger, and chains. What we need are MPLAB® ICD2 Debugger/Programmer and C30® ANSI C compiler. I know, they are both new tools, but they will do the job–trust me with this one. Please be aware you can download for free C30 compiler, fully functional for 60 days, from Microchip.

Now we have everything we need to start the infernal process of taming the beast, and I am certain you think this is a long and very difficult burden. Well, it is not. What you need is a good incantation, like the multitasking one described in… No, I will not make it that easy, but I will give you a hint: you will discover the book with the ritual I am talking about at Corollary Theorems–my home site. You will also discover a good cage there to contain the monster, securely: its name is HCK (Hardware Companion Kit) V2.2.

This is all! It should take you a couple of months to break the dsPIC20F4011 monster down. Then, you will have a yoke-beast ready to perform everything you need: all your tasks and all applications! I am certain your little monster is going to repay you back nicely, for all your efforts. In time, you two are going to become good friends, and you will come to love and respect your little dsPIC30F4011.

O G POPA is Professional Engineer in BC, Canada. His home site is Corollary Theorems at http://www.corollarytheorems.com

Junk faxes waste the resources of every business. It is estimated that they cost businesses tens of millions of dollars a year in wasted paper, toner and fax machine maintenance. There is nothing more aggravating then coming into the office each morning to find a pile of junk faxes promotion everything from mortgage refinancing to septic tank solutions. I don’t even have a septic tank!

Junk fax companies have been fined by the federal government and sued repeatedly, but has anyone noticed a reduction in the number of junk faxes? I certainly haven’t. The question for most businesses is whether there is a practical way to beat the daily waste of resources caused by junk faxes? Many businesses are using the fax-to-email solution provided through online unified messaging systems.

What is Unified Messaging?

Unified Messaging is a highly flexible communication system that ties all of your communications together. It has the capacity to centralize your voice mail, faxes and email messages in one online area through an email address and single phone number. These systems use their own phone lines and provide you with a separate number, so you don’t have to tie up your own or have an additional line installed.

Fax to Email Conversion

One of the best aspects of Unified Messaging systems is the fax-to-email conversion feature. You are provided with a phone number where people can send you faxes and leave voice mail messages. The beauty of the system is that the faxes are then automatically converted to text files and emailed to an inbox.

So, how does this save you money? You simply delete the junk faxes unless, of course, you need to “maximize the potential of your septic tank.” You then read or print out the faxes that are germane to your business. No wasted paper, no wasted toner and no smoke coming out of your fax machine!

An added advantage of the fax-to-email conversion element of unified messaging is the flexibility it gives you. Since the faxes are available to you online, you can print the ones you need at any location. You no longer have the frustrating situation where you are working at home, but need to see a fax that was just sent to your office. You just access your inbox and print it out.

The cost of using unified messaging is very low, particularly when compared to the cost of wasted paper, toner and fax machine maintenance. Depending on the service you use, you may be charged a monthly signup fee, by the minute for phone line usage or both. The best option for your business is entirely dependent upon the number of faxes you expect to receive each month.

Despite the lawsuits and fines issued by government agencies, there is little doubt that junk faxes will continue to bombard your fax machines. Unified messaging provides an inexpensive and practical way to eliminate the cost of junk faxes.

About The Author

Barry Waxler is the President of http://3in1box.com - your unified messaging solution. Visit http://www.3in1box.com to get your FREE unified messaging box or contact Barry at BarryWaxler@3in1box.com

There’s a widespread confusion among Cisco customers as to what the difference really is between Cisco approved memory modules and their third party counterparts.

First of all, it should be clear to anyone interested in this subject that Cisco Systems simply does not manufacture any of its memory parts!

The memory parts customers get when they purchase Cisco equipment are manufactured by a Cisco approved OEM (Original Equipment Manufacturer). The OEM could be any company from Cisco’s Approved Vendor List (AVL) which includes companies such as OKI Semiconductor, NEC Electronics, and Samsung among others. It should also be noted that since Cisco Systems no longer releases its AVL to the public, thus the companies mentioned above may or may not still be on the AVL. There will definitely be new companies added from time to time and companies removed as well.

Approved/OEM or "first party" Cisco memory refers to memory parts manufactured by companies on Cisco’s AVL; these memory modules have been engineered specifically for use by Cisco Systems and undergo strict and comprehensive testing before being approved by Cisco for use with their routers and other products. These modules are guaranteed to have 100% compatibility with their corresponding Cisco equipments and are backed by a lifetime warranty.

Third party memory modules on the other hand are manufactured by companies not on Cisco’s AVL and are not tested nor approved by Cisco Systems. The manufacturer does offer warranty and compatibility guarantee for these memory modules but Cisco does not. And although manufacturers of such memory modules claim to be fully compliant with Cisco’s specifications, Cisco does hold the right to refuse service, under warranty, when the fault is deemed to be caused by the 3rd party memory modules; and even if this was only discovered later on then Cisco will bill the customer for the service.

And while 3rd party memory modules are cheaper and useful for certain groups such as students learning about Cisco equipment, they do pose a certain level of risk for any business considering using these modules. Think about any unnecessary downtime and how much that will cost your business. Approved memory modules have undergone stringent testing by Cisco Systems themselves for use with Cisco’s own equipment, they do not affect the service warranty of the equipment they are used in and the memory modules themselves are covered by a lifetime warranty.

It is simply the smarter business choice for any company to opt for approved Cisco memory modules. Even though the initial cost might seem higher, but in the long run they are actually cheaper as there is extremely low probability, if any, of incompatibility or faults. Approved Cisco memory results in a lesser need to maintain and service these modules and the equipment they are used in; think total cost of ownership.

Sabir Rizvi is a seasoned IT professional who writes for CiscoUpgrade.com, an online store that specializes in selling cisco approved memory at discounted prices. Visit the website to read more of his articles at http://www.CiscoUpgrade.com

This article focuses on frequently asked questions by buyers of plasma and LCD televisions.

Q: Does the "plasma" in plasma televisions need to be recharged or replaced over time?

A: No. The plasma gases are sealed in individual cells when they are manufactured. There is no way to recharge or replace the gases. However, plasma TVs, when used normally, will last you many, many years (up to 20 years) so you don’t have to worry about the screen burning out for a long time.

Q: Are plasma and LCD TVs difficult to install?

A: While you may want to hire a professional electrician to help you with wiring if you are installing your plasma or LCD television on a wall, you can also easily place the television on a stand yourself and place it anywhere you like.

Q: Do plasma and LCD TVs give off radiation?

A: All electronic devices, including televisions, must comply with FDA guidelines (in the United States) and CSA guidelines (in Canada) on radiation emission before being permitted to be sold to the public. While there is radiation emission in the form of ultraviolet light, the amount is negligible and you are unlikely to be affected by it watching the television from normal distances.

Q: What are anamorphic widescreen DVD movies?

A: There are two common ways of recording wide format movies on a DVD: letterbox and anamorphic. Letterbox refers to a video played with horizontal black bars on the top and bottom of the picture. Anamorphic recordings are also commonly labeled “Enhanced for 16:9 TVs”. Anamorphic recordings have over 30% more vertical resolution than letterbox format and elimates or significantly reduces the black bars found in letterbox pictures in order to fit to the screen size of 16:9 televisions.

Q: Do LCD’s have a burn-in problem?

A: No. Unlike CRT and plasma TVs, liquid crystal displays do not use phosphor and thus have no problems with a still image becoming permanently stored on the screen. Instead, LCD TVs use a backlight on a colored, transluscent liquid crystal screen.

Q: Can I use a game console such as Sony Playstation 2, Nintendo Game Cube or Microsoft XBOX with my LCD TV?

A: Yes. If you intend to use a game console and/or watch standard TV broadcasts over cable, satellite or antenna, an LCD TV is a superior choice over plasma televisions. The repetitive image from games and unused black-filled borders will damage a plasma TV by burning a permanent image into the phosphor.

Q: Will leaving my LCD TV on cause the image to degrade?

A: No. Unlike plasma TV’s, this LCD TV does not exhibit aging over time. The brightness of the image remains the same because LCD televisions use a florescent backlight.

Q: Can I mount my LCD TV straight into drywall or plaster?

A: No, drywall or plaster alone will not offer enough support. A structural beam or stud must be used as the anchor for the wall mount.

(c) 2005 Philip Liu - All Worldwide Rights Reserved

Philip Liu is a freelance author and publisher currently based in New York City. Philip publishes regularly on his websites dealing with cell phone reviews and news and plasma, LCD TV reviews and news.

First a little history….

In 1938, the first invention that would lead to the laser printer and toner cartridge was patented. The process, knows as "electro photography", used a dry printing method, not that different than today’s laser printer. It was 1948, however, before the commercial application of electro photography because available.

In 1959, the first automatic reproduction machine, the Xerox 914, which used a dry printing process. In 1978, the fine tuned technology was applied to the computer printing needs of business and private citizens. Physically large and with a large price tag as well, the Xerox 9700 laser printer that used a toner cartridge wasn’t affordable by individuals except the wealthy.

Everything changed in 1984 when Hewlett Packard began to market the "LaserJet" printer. This printer came with a replaceable toner cartridge that was not difficult to change, although it could sometimes bit a little messy. The really problematic part was that people who used the LaserJet had stacks of expensive but empty toners stacked in the storage room or wherever they could find to store the toner cartridges.

This problem was quickly resolved by environmentally aware designers by re-manufacturing the laser toner cartridge. This significantly reduced the cost of using laser printers.

What’s happening today?….

Nowadays we have the luxury of having a laser printer on our desk at home if we want that type of printing. The as well as the initial outlay for the printer has become quite affordable and provides a unique, very professional looking print out.

Today, laser printers are manufactured by many companies and the price tag is only slightly more than the common ink printer (though colour laser printers are still quite expensive the gap is getting smaller). The laser toner cartridge costs have been reduced so that it is reasonable to use the laser printer at home as well as at the office. In fact the toners are usually much cheaper when you take into account the larger number of pages you get for the amount you pay (the industry uses the terminology ‘cents per page’ or CPP)

Basically there are 2 types of cartridges, originals and non-originals and there are 2 types of non-originals being compatibles and remanufactured (this goes for inks also as does the information below). Otherwise known as non genuine, after market this is how they work:-

- Compatibles are actually a brand new cartridge manufactured to work in the same way (without breaking the trademark, copy protection laws) as the same original cartridge with the same machines. The benefit you gain from these is obviously cost savings with at times massive savings up to around 50%. The downside is they are not as environmentally friendly as remanufactured toners and there are the occasional failures and complaints about lower quality (though failure rates for the top companies making these are within industry norms and not significantly higher than those of the original manufacturers themselves)

- Remanufactured toners however are a little different as they take an empty original (it should have only been used ONCE) and fill it with toner. As long as you buy from a reputable retailer it will have also been checked to determine if parts need to be replaced as well as toner refilled. You also get good cost savings as you do with compatibles but the environment wins out big time as you helping ‘close the loop’ by reusing an empty original. Once again the same applies as above with quality and failures (both negligible in my experience as a retailer in this industry).

NOTE: Its worth making a special note here that disposing of empty toners is a problem worldwide as the plastic they’re made of takes so long to break down and the toxicity of the toner inside. In many countries today there are programs available where you can get rid of your empties without just throwing them in the bin. In fact if you hunt around you’ll probably find a company will pay you for them as they need a constant stream of empties coming through so they can remanufacture them.

Something to keep in mind….

When purchasing a re-manufactured laser toner cartridge, be sure to read the box carefully and ensure you are selecting the right toner cartridge. The first time you purchase a re-manufactured toner cartridge, the box may look entirely different or very plain because these inexpensive toners are often not packaged in fancy, colourful boxes like the name brands. But then they don’t cost what the name brand toners do, either.

The bottom line….

If you use a reputable retailer for your home/office supplies they should have a clear policy in place not only about faulty toners but what happens if a cartridge has somehow caused damage to your machine (this would be very unusual by the way). Under these circumstances this policy should give you a full warranty to have the equipment repaired ASAP at no cost to you.

With my clients when they ask what I suggest I always recommend they try a non-original to see for themselves the quality etc. In any case the trick is to be able to make an informed choice with someone you trust so at least if something goes wrong the people you bought from haven’t skipped the country.

Andrew James has owned The Cartridge Specialists (Melbourne, Australia) since 2004 selling ink & toner cartridges, and other printing/office supplies. As a regular author of articles in his industry Andrew can help you save money at home or office and have fun learning about your high tech toys.

When purchasing a flat panel TV, there are a few things to keep in mind. Here, we’ve listed a number of considerations for you to evaluate.

High Definition Upgradeable or HDTV-Ready

If you see either of these terms used when deciding to purchase a flat screen TV, it means that the TV is capable of producing the highest resolutions possible for digital television today. “Upgradeable” means that you’ll need to first add a separate HDTV receiver before you can view the pictures in high definition mode (1080i or 720p). But, even if you don’t upgrade, the picture will still look fantastic. When watching regular DVDs or TV broadcasts, the picture will be almost as good as real HDTV because most have line-doublers to improve the picture.

16:9 Aspect Ratio

Unlike conventional televisions, new plasma, LCD and rear-projection televisions most likely have a wide, rectangular screen that is very similar to the shape of a movie screen. This is known as 16:9 aspect ratio—for every 16 inches wide, the screen is 9 inches high. Compared to conventional TVs, which are 4:3 in aspect ratio, the field of vision is wider for a new flat screen TV.

When watching DVDs at home on a 16:9 wide-screen television, you will be able to enjoy the full screen effect of the movie the way it was intended. On the other hand, when watching regular, standard definition television (like a news broadcast or talk show), you will need to either set the television to fill the screen entirely or watch with vertical black bars on either side of the picture.

Finally, remember that even though most television broadcasts are in 4:3 format, 16:9 widescreen format is the way of the future. Many events are shot in HDTV format (for example, the Olympics, special sporting events, nature documentaries, etc.) and as more and more people purchase high definition television, all broadcasts will be in high definition within the next few years.

Reverse 3:2 Pulldown

Television shows are usually shot on film at 24 frames per second. When transferred to video running at 30 frames per second, the picture quality is distorted in the translation. New televisions are able to correct those distortions through a series of reconversion techniques which reverse the distortions. The result is a smoother and cleaner picture.

When looking to buy a new plasma, LCD or rear-projection television, look for this feature.

3D Y/C Digital Comb Filter

The 3D Y/C digital comb filter’s job is to take the cable signal coming from the wall and separate the color, sound, brightness information into useable information. New plasma, LCD and rear-projection televisions have digital 3D Y/C comb filters that do a pretty good job of this so as to avoid what is know as “dot crawl” where the edges of objects appear rough. In addition, a good digital comb filter will also counter the effects of moiré, where still objects appear to move and ripple.

Most high end plasma, LCD and rear-projection televisions also have component inputs from video sources (such as a DVD player) that separate the signal before reaching the TV and bypass the digital comb filter. This results in an even clearer and brighter picture.

Picture-in-Picture

Picture-in-Picture (or PIP) allows you to watch two shows at once, with the second show in a box in a part of the screen. PIP is fairly common these days to all sorts of televisions. However, consider getting a dual tuner PIP plasma, LCD or projection television since that allows you to watch the second channel without needing an external tuner (for example, from a vcr). In addition, there are also TVs that will show different channels side by side—these are called twin view PIP TVs.

Inputs

“Inputs” refer to how related audio/visual components connect to your plasma, LCD or rear-projection television. The highest video quality input is known as “component video”. With component video inputs, the color and brightness information from the cable is separated into useable data before entering the television. The next best input is S-video input which give a picture almost as good as component video—whereas component video separates brightness, blue signal and red signal from each other, S-video just separates brightness from blue and red signals.

All new plasma, LCD and rear-projection televisions will also have inputs for various multimedia devices such as DVD players. In addition, some will allow you to connect a computer.

(c) 2005 Philip Liu - All Rights Reserved Worldwide

Philip Liu is a freelance author and publisher currently based in New York City. Philip publishes regularly on his websites dealing with cell phone reviews and news and plasma, LCD TV reviews and news.

The big boys in the computer industry want you to continue thinking the way you are. The major desktop computer manufacturers thrive on consumers lack of knowledge and old ideas about desktop computers and computer hardware to drive sales of new desktop computers.

It works in their favor to keep these myths alive, because their business depends on it. So what are they?

Myth 1: You need top of the line computer hardware

Maybe some years ago this might have been true with older computer hardware, but times have changed. When computers were much slower than they are now, the latest version of any computer hardware increased speeds noticeably and allowed new possibilities from your desktop computer.

Those increases from computer hardware no longer yield such a huge increase in performance. With the basic uses of the desktop computer set and been in place for a while now, speed increases no longer result in real world benefits for most desktop computer users.

What was great computer hardware last year is still good enough now.

Myth 2: Computer hardware is the domain of Geeks

When personal computing was coming into its own, you really did need to be a Geek to know what was happening. For those old enough to remember, imagine life without Windows and hacking away at the command line, as used to be the case. Some still do, but I wouldn’t want to do that again.

Desktop computers are such commonplace that the basics of computer hardware can be understood and researched with the minimum of hassle. The ball is on the consumers side of the court. You no longer need to be a geek, just a little knowledge that is now readily available.

Myth 3: A faster desktop computer will speed up the Internet

Possibly. If you are running 5-year-old computer hardware this might be the case. But the real reason for the increase in speed is usually not the computer.

Internet speed is related to your connection speed. If you have a dial up connection, it’s going to be quite slow. When you upgrade your desktop computer and they throw in a cable internet, or DSL package the improved speed is from the faster connection, not the computer. Both cable and DSL can offer more than 10 times the speed of a dial-up connection. The computer has little to do with it.

Myth 4: To speed your computer up, upgrade!

New computer hardware is a very obvious way to speed things up. Even I have gone for new parts purely for this reason.

But it’s definitely not the only way.

Various factors play into overall speed. On a purely physical level, upgrading memory is still a fantastic way to get things to move along a little faster. But apart from this the main things that slows things down on the programs and other stuff you have on the computer.

Over time, as more programs are put on and taken off and changed, things get left behind, and things get forgotten. When your computer starts, many things get loaded into memory and each one of those takes that little bit more of the computers resources. When you switch to a new program and don’t remove the old one, the older one will still use resources.

Myth 5: Big brands are the best

Big brands essentially piece together a computer. They pick and choose the pieces to make a computer package. They also choose some software, give a warranty and then sell it to you.

Dell computer company has become well known for its customer service. This is the best part about Dell computers. The downside is there are limited choices. They pick what goes into the computer, which are often quite expensive parts. They are motivated by the suppliers to put more recent parts into their computers, keeping the prices at the same level and maintaining the "to get more, pay more," mentality.

You don’t have the power of these big guys, but you have something more. Choice.

Your pick of parts for your desktop computer will allow you to put together something completely tailored to your needs. Put the money where you need it most, into the computer hardware that makes the biggest difference to you, and in the end getting a desktop computer you will fall in love with, rather than despise.

Get the most honest and useful reviews to make the right choice at our Desktop Computer Hardware Reviews site or get practical computer buying tips at our Computer Buying Guide site

ROUTING PROTOCOLS

A generic term that refers to a formula, or protocol, used by a router to determine the appropriate path over which data is transmitted. The routing protocol also specifies how routers in a network share information with each other and report changes. The routing protocol enables a network to make dynamic adjustments to its conditions, so routing decisions do not have to be predetermined and static.

Routing, Routed and Non-Routable Protocols

ROUTING | ROUTED | NON-ROUTABLE

ROUTING PROTOCOLS

ROUTING PROTOCOLS are the software that allow routers to dynamically advertise and learn routes, determine which routes are available and which are the most efficient routes to a destination. Routing protocols used by the Internet Protocol suite include:

· Routing Information Protocol (RIP and RIP II).
· Open Shortest Path First (OSPF).
· Intermediate System to Intermediate System (IS-IS).
· Interrior Gateway Routing Protocol (IGRP).
· Cisco’s Enhanced Interior Gateway Routing Protocol (EIGRP).
· Border Gateway Protocol (BGP).

Routing is the process of moving data across two or more networks. Within a network, all hosts are directly accessable because they are on the same

ROUTED PROTOCOLS

ROUTED PROTOCOLS are nothing more than data being transported across the networks. Routed protocols include:

· Internet Protocol
o Telnet
o Remote Procedure Call (RPC)
o SNMP
o SMTP
· Novell IPX
· Open Standards Institute networking protocol
· DECnet
· Appletalk
· Banyan Vines
· Xerox Network System (XNS)

Outside a network, specialized devices called ROUTES are used to perform the routing process of forwarding packets between networks. Routers are connected to the edges of two or more networks to provide connectivity between them. These devices are usually dedicated machines with specialized hardware and software to speed up the routing process. These devices send and receive routing information to each other about networks that they can and cannot reach. Routers examine all routes to a destination, determine which routes have the best metric, and insert one or more routes into the IP routing table on the router. By maintaining a current list of known routes, routers can quicky and efficiently send your information on it’s way when received.

There are many companies that produce routers: Cisco, Juniper, Bay, Nortel, 3Com, Cabletron, etc. Each company’s product is different in how it is configured, but most will interoperate so long as they share common physical and data link layer protocols (Cisco HDLC or PPP over Serial, Ethernet etc.). Before purchasing a router for your business, always check with your Internet provider to see what equipment they use, and choose a router, which will interoperate with your Internet provider’s equipment.

NON-ROUTABLE PROTOCOLS

NON-ROUTABLE PROTOCOLS cannot survive being routed. Non-routable protocols presume that all computers they will ever communicate with are on the same network (to get them working in a routed environment, you must bridge the networks). Todays modern networks are not very tolerant of protocols that do not understand the concept of a multi-segment network and most of these protocols are dying or falling out of use.

· NetBEUI
· DLC
· LAT
· DRP
· MOP

RIP (Routing Information Protocol)

RIP is a dynamic internetwork routing protocol primary used in interior routing environments. A dynamic routing protocol, as opposed to a static routing protocol, automatically discovers routes and builds routing tables. Interior environments are typically private networks (autonomous systems). In contrast, exterior routing protocols such as BGP are used to exchange route summaries between autonomous systems. BGP is used among autonomous systems on the Internet.

RIP uses the distance-vector algorithm developed by Bellman and Ford (Bellman-Ford algorithm).

Routing Information Protocol

Background

The Routing Information Protocol, or RIP, as it is more commonly called, is one of the most enduring of all routing protocols. RIP is also one of the more easily confused protocols because a variety of RIP-like routing protocols proliferated, some of which even used the same name! RIP and the myriad RIP-like protocols were based on the same set of algorithms that use distance vectors to mathematically compare routes to identify the best path to any given destination address. These algorithms emerged from academic research that dates back to 1957.

Today’s open standard version of RIP, sometimes referred to as IP RIP, is formally defined in two documents: Request For Comments (RFC) 1058 and Internet Standard (STD) 56. As IP-based networks became both more numerous and greater in size, it became apparent to the Internet Engineering Task Force (IETF) that RIP needed to be updated. Consequently, the IETF released RFC 1388 in January 1993, which was then superceded in November 1994 by RFC 1723, which describes RIP 2 (the second version of RIP). These RFCs described an extension of RIP’s capabilities but did not attempt to obsolete the previous version of RIP. RIP 2 enabled RIP messages to carry more information, which permitted the use of a simple authentication mechanism to secure table updates. More importantly, RIP 2 supported subnet masks, a critical feature that was not available in RIP.

This chapter summarizes the basic capabilities and features associated with RIP. Topics include the routing update process, RIP routing metrics, routing stability, and routing timers.

Routing Updates

RIP sends routing-update messages at regular intervals and when the network topology changes. When a router receives a routing update that includes changes to an entry, it updates its routing table to reflect the new route. The metric value for the path is increased by 1, and the sender is indicated as the next hop. RIP routers maintain only the best route (the route with the lowest metric value) to a destination. After updating its routing table, the router immediately begins transmitting routing updates to inform other network routers of the change. These updates are sent independently of the regularly scheduled updates that RIP routers send.

RIP Routing Metric

RIP uses a single routing metric (hop count) to measure the distance between the source and a destination network. Each hop in a path from source to destination is assigned a hop count value, which is typically 1. When a router receives a routing update that contains a new or changed destination network entry, the router adds 1 to the metric value indicated in the update and enters the network in the routing table. The IP address of the sender is used as the next hop.

RIP Stability Features

RIP prevents routing loops from continuing indefinitely by implementing a limit on the number of hops allowed in a path from the source to a destination. The maximum number of hops in a path is 15. If a router receives a routing update that contains a new or changed entry, and if increasing the metric value by 1 causes the metric to be infinity (that is, 16), the network destination is considered unreachable. The downside of this stability feature is that it limits the maximum diameter of a RIP network to less than 16 hops.

RIP includes a number of other stability features that are common to many routing protocols. These features are designed to provide stability despite potentially rapid changes in a network’s topology. For example, RIP implements the split horizon and holddown mechanisms to prevent incorrect routing information from being propagated.

RIP Timers

RIP uses numerous timers to regulate its performance. These include a routing-update timer, a route-timeout timer, and a route-flush timer. The routing-update timer clocks the interval between periodic routing updates. Generally, it is set to 30 seconds, with a small random amount of time added whenever the timer is reset. This is done to help prevent congestion, which could result from all routers simultaneously attempting to update their neighbors. Each routing table entry has a route-timeout timer associated with it. When the route-timeout timer expires, the route is marked invalid but is retained in the table until the route-flush timer expires.

Packet Formats
The following section focuses on the IP RIP and IP RIP 2 packet formats illustrated in Figures 44-1 and 44-2. Each illustration is followed by descriptions of the fields illustrated. RIP Packet Format

· Command—Indicates whether the packet is a request or a response. The request asks that a router send all or part of its routing table. The response can be an unsolicited regular routing update or a reply to a request. Responses contain routing table entries. Multiple RIP packets are used to convey information from large routing tables.

· Version number—Specifies the RIP version used. This field can signal different potentially incompatible versions.

· Zero—This field is not actually used by RFC 1058 RIP; it was added solely to provide backward compatibility with prestandard varieties of RIP. Its name comes from its defaulted value: zero.

· Address-family identifier (AFI)—Specifies the address family used. RIP is designed to carry routing information for several different protocols. Each entry has an address-family identifier to indicate the type of address being specified. The AFI for IP is 2.

· Address—Specifies the IP address for the entry.

· Metric—Indicates how many internetwork hops (routers) have been traversed in the trip to the destination. This value is between 1 and 15 for a valid route, or 16 for an unreachable route.

Note: Up to 25 occurrences of the AFI, Address, and Metric fields are permitted in a single IP RIP packet. (Up to 25 destinations can be listed in a single RIP packet.)

RIP 2 Packet Format

· Command—Indicates whether the packet is a request or a response. The request asks that a router send all or a part of its routing table. The response can be an unsolicited regular routing update or a reply to a request. Responses contain routing table entries. Multiple RIP packets are used to convey information from large routing tables.

· Version—Specifies the RIP version used. In a RIP packet implementing any of the RIP 2 fields or using authentication, this value is set to 2.

· Unused—Has a value set to zero.

· Address-family identifier (AFI)—Specifies the address family used. RIPv2’s AFI field functions identically to RFC 1058 RIP’s AFI field, with one exception: If the AFI for the first entry in the message is 0xFFFF, the remainder of the entry contains authentication information. Currently, the only authentication type is simple password.

· Route tag—Provides a method for distinguishing between internal routes (learned by RIP) and external routes (learned from other protocols).

· IP address—Specifies the IP address for the entry.

· Subnet mask—Contains the subnet mask for the entry. If this field is zero, no subnet mask has been specified for the entry.

·Next hop—Indicates the IP address of the next hop to which packets for the entry should be forwarded.

· Metric—Indicates how many internetwork hops (routers) have been traversed in the trip to the destination. This value is between 1 and 15 for a valid route, or 16 for an unreachable route.

Note: Up to 25 occurrences of the AFI, Address, and Metric fields are permitted in a single IP RIP packet. That is, up to 25 routing table entries can be listed in a single RIP packet. If the AFI specifies an authenticated message, only 24 routing table entries can be specified. Given that individual table entries aren’t fragmented into multiple packets, RIP does not need a mechanism to resequence datagrams bearing routing table updates from neighboring routers.

Summary

Despite RIP’s age and the emergence of more sophisticated routing protocols, it is far from obsolete. RIP is mature, stable, widely supported, and easy to configure. Its simplicity is well suited for use in stub networks and in small autonomous systems that do not have enough redundant paths to warrant the overheads of a more sophisticated protocol.

Review Questions

Q—Name RIP’s various stability features.
A—RIP has numerous stability features, the most obvious of which is RIP’s maximum hop count. By placing a finite limit on the number of hops that a route can take, routing loops are discouraged, if not completely eliminated. Other stability features include its various timing mechanisms that help ensure that the routing table contains only valid routes, as well as split horizon and holddown mechanisms that prevent incorrect routing information from being disseminated throughout the network.

Q—What is the purpose of the timeout timer?
A—The timeout timer is used to help purge invalid routes from a RIP node. Routes that aren’t refreshed for a given period of time are likely invalid because of some change in the network. Thus, RIP maintains a timeout timer for each known route. When a route’s timeout timer expires, the route is marked invalid but is retained in the table until the route-flush timer expires.

Q—What two capabilities are supported by RIP 2 but not RIP?
A—RIP 2 enables the use of a simple authentication mechanism to secure table updates. More importantly, RIP 2 supports subnet masks, a critical feature that is not available in RIP.

Q—What is the maximum network diameter of a RIP network?
A—A RIP network’s maximum diameter is 15 hops. RIP can count to 16, but that value is considered an error condition rather than a valid hop count.

This article is submitted by Kashif Raza http://www.networkingtutorials.net

Have you ever wanted you ever wanted your own troubleshooting guide for your toner cartridges?

Well here you go!

Your Toner Cartridge Troubleshooting Guide:

Below are some common problems that may show up during your printer usage. Here’s what will happen and how to fix them:

•Dirty PCR (primary charge roller): A dirty PCR, which is located inside the printer, will cause vertical gray streaks down the test page or create a gray background on the entire page.

•Scratched Drum: This condition is indicated by a very thin, perfectly straight line that runs from the top to the bottom of the test page.

•Chipped Drum: A chipped drum will make a dot or series of dots that repeat three times per page. Any drum defects will repeat three times per page based on the drum circumference of 5.2”.

•Light Damaged Drum: This condition will show up as a shaded area on the test print that normally should be white. Again, this will repeat three times per page.

•Bad Wiper Blade: A bad wiper blade will make either a gray line approximately 1/8” thick or shading across the entire page. In either case, there will be a film of toner on the drum surface.

•Weak Doctor Blade Spring: This will usually show as shaded areas on one or both sides of the page.

Machine Error Codes:

•32 Unsupported Print Cartridges: (Wrong chip, encoder wheel combination or bad chip). If this code appears immediately upon cartridge installation, there is either a bad contact or the chip is bad. If the machine cycles and then the message appears, the wrong encoder wheel is installed. In the T632 machines, this message will also show if the extra high yield cartridge is not installed.

•80 Scheduled Maintenance: The code appears when 300,000 pages have been printed.

•88 Toner Low: Add toner.

•200-280 Indicates various paper jams.

Taking Test Print:

-Printer Menu: Press the “MENU” key until “Utilities Menu” is displayed.
-Press “SELECT.”
-Press the “MENU” key until “Print Menu” is displayed.
-Press “SELECT.”

Font Sample:

-Press the “MENU” key until “Utilities Menu” is displayed.
-Press “SELECT.”
-Press the “MENU” key until “Print Fonts” is displayed.
-Press “SELECT.”
-Select either the PCL fonts or the Postscript fonts.
-Press “SELECT.”
-The Print Menu page contains the printer page count, toner level, cartridge serial number, cartridge size, whether it’s Prebate or not, and the cartridge type (Normal, MICR, or Label).

Changing the Printer Density:

-Press the “MENU” key until “Quality Menu” is displayed.
-Press “SELECT.”
-Press the “MENU” key until “Toner Darkness” is displayed.
-Press “SELECT.”
-Choose a number between 1 and 10. “8” is the default setting.

Changing the Printer Resolution:

-Press the “MENU” key until “Quality Menu” is displayed.
-Press “SELECT.”
-Press the “MENU” key until “Print Resolution” is displayed.
-Press “SELECT.”

*Note: The options available are 300, 600, 1200 Image Q, and 1200 dpi (dots per inch). The 1200 Image Q is for bitmapped pictures. The printer’s default is 600 dpi (dots per inch).

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High definition DVD, also known as HD-DVD (which actually stands for High Density DVD), is one of two competing high definition storage format - the other being Blu-ray.

The need for a new, high capacity storage format, has been primarily brought about by the rapid rise in popularity of HDTV in Japan and the US. HDTV has much higher bandwidth than either NTSC or regular DVD discs, so in order to record programs from HD- DVD higher capacity discs, of at least 30GB, are required.

High definition video is also being used increasingly to make Hollywood movies as it offers comparable quality to film at much less cost. Therefore, the studios plan to release future movies on one or both high definition formats.

HD-DVD was developed by Toshiba and NEC and has the support of the DVD Forum, along with a number of Hollywood studios. Currently those studios which have announced support for HD-DVD are; Universal Studios, Paramount Studios, Warner Bros., and New Line Cinema. It has a capacity of 15GB for single-sided discs and 30Gb for double-sided. It doesn’t need a caddy or cartridge and the cover layer is the same thickness as current DVD discs, 0.6mm. The numerical aperture of the optical pick-up head is also the same as DVD, 0.65mm.

Because of its similarities to current DVD, high definition DVD is cheaper to manufacture than Blu-ray, because it doesn’t need big changes in the production line set-up. Both HD-DVD and Blu-ray have backward compatibility with existing DVDV discs. That is that current DVDs will play in HD-DVD player, although new high definition DVD won’t play in older DVD players.

High definition DVD currently supports a number of compression formats, including MPEG-2, VC1 (based on Microsoft’s Windows Media 9), and H.264 which is based on MPEG-4 and will be supported by the next version of Apple’s QuickTime software, which will be included with Mac OS X Tiger.

Kenny Hemphill is the editor and publisher of The HDTV Tuner - a guide to the kit, the technology and the programming on HDTV.