When it comes to wireless internet connectivity, we all want to buy the best wireless router. Because the internet is so much a part of our lives nowadays, we would not want to risk internet disconnection just because of an unreliable router.

Your first challenge in buying the best wireless router is sorting through the various brands of networking devices now sold in the market. To find the right one, use the following tips:

Tip 1: Do not always go for high-speed routers

High speed is what we are all looking for. However, high speed routers do not guarantee a high speed internet connection. According to router experts, most high speed router models do not even use the average of the speed they promise. Spending extra money on such a model of router might not be ideal. Choose only those with mid-level speed. If your internet connection is fast enough, transmission will be good enough.

Tip 2: Choose the right design and size

Many people are not really particular about the design of the router they are buying. They are mostly particular about the functionality of the router. The size and design of the router you are buying will depend on the space allotted for your router in your room.

Tip 3: Do not just rely on reviews to determine the reliability of the router

There is a mix of positive and negative accountings about the brand of router. The experiences are not the same. Also, some people are very critical about the speed and the transmission of their routers. Some have higher standards. For home use, you don’t really need a fussy router. You can just stick to those simpler models. The security of the router can just be configured. So don’t let the good and bad reviews decide for you.

Tip 4: Choose between those with external or internal antennas

According to networking experts those products with external antennas deliver stronger signals. There are certain brands of routers with more than one antenna. If you have a large house and you would want to get full signal anywhere in the house, you should choose a router than can deliver stronger signal. Many also prefer buying this with internal antennas. That is because they are less conspicuous compared to its external counterpart. They just use a signal amplifier to increase signal transmission.

Just consider these steps when you are buying so you can choose only the best wireless router for your home.

The Vanagon Weekender is the most convenient, spacey and well configured camper van ever used. The 1983-1991 Vanagon Weekenders have water-cooled horizontally opposed engine with Digifant electronic fuel injection and 90HP at 4800RPM that are 1.9 liter (1983-1985) and a 2.1 liter (1986-1991). Vanagon Weekender camper van attributes a 4-speed manual transmission or an automatic transmission with electronic ignition, dynamic oil pressure system, and a thermostatically controlled 2-speed electric radiator fan. The towing capacity of the van is hampered due to the size of its engine but the van can prove a greater efficient in towing small trailers if equipped with brakes. Particularly, the van is even more resourceful as it does not have the extra load of the full Camper.

How would you like a little extra space for your luggage? With cargo capacity of nearly 100 cubic feet, the van stands out as the most preferable camper vans, which is pretty exciting. More over the van has roof-top luggage carrier with tie-down bars for extra storage. And if you still need some room, then you have some space under the rear bench and a wardrobe closet with sliding door. With a seating capacity of 7, the Vanagon Weekender will be a perfect choice for a comfy trip with your family and friends.

The van has forward-facing center bench that converts into a 3-person bed and 2 rear-facing seats that can be detached to increase cargo space if needed. It has two Front seats that swivel 360 degrees and have adjustable armrests. Three point belts for the captain seats, Height adjustable head restrains for each seat, Side impact beams in front doors and slide side doors are the special feature that enhances the safety of the van. On the other hand, the storage capacity of LP and water is also more in the van. 15.9-gallon capacity gasoline tank, 5.9-gallon LP gas tank and 12-gallon capacity fresh water tank are excessively useful for a long and safe trip.

Almost all these vans come usually with power windows, rear-blowing air conditioning, electronic locks, cruise control, cassette stereo, rear wiper, Rear-blowing air conditioning, and power mirrors. Additional to these, the Vanagon Weekender vans comes-up with pop-up roof that has 2-person bed, window curtains, an second deep-cycle marine battery (optional) and many more exiting add-ons. AC/DC/LP gas refrigerator of 2 cubic feet, two-burner LP gas stove with stainless steel splatter shield, Dining cum utility tables, AC-to DC power converter with coach battery charger, Fluorescent lights over gallery and lower bed, pleated curtains for side windows that acts as room darkeners, Privacy curtains to separate the front cab and rear hatch windows are the other additional luxuries.

Vanagon Weekender is not just a tour vehicle that can keep you at ease during your travel, but it can also serve as the best means of transport for your other everyday usage.

While only providing about 1% of U.S. electricity needs, wind power is growing more rapidly than any other energy source. Over 5,000 megawatts of new wind generating capacity was installed in the U.S., in 2007, second only to new natural gas-fired generating capacity. Wind technology has improved extensively over the past two decades; however wind energy still depends on federal tax incentives to compete with traditional energy sources. A large obstacle for grid parity using wind energy is that its production is dependent on when the wind is blowing rather than peak consumer power needs. This variability creates added expenses and complexity for balancing supply and demand on the grid. An additional issue is that new transmission infrastructure will be required to deliver wind-generated power to high density population centers. Because building new transmission lines are expensive and time-consuming, it is difficult to determine how construction costs should be allocated among consumers and which pricing methodologies to use.

To date, U.S. federal wind power policy has centered on the production tax credit The Production Tax Credit is a business incentive to operate wind facilities. However, this credit expired on December 31, 2008. Policy analysts and wind industry representatives have argued that the on-again off-again nature of the production tax credit is inefficient and actually leads to higher costs for the industry.

According to the 2008, CRS Report for Congress, “Wind Power in the United States: Technologies, Economic and Policy Issues,” wind turbines have no fuel costs, and minimal variable operations and maintenance (O&M) expenses. Also, wind power does not have the other costs that come with fossil fuel burning, such as air pollution control equipment. Nor does wind power incur the waste disposal costs associated with other energy generation, such as scrubber sludge disposal for coal plants and waste storage for nuclear plants. However, although wind plants have low variable costs, the fixed O&M costs are high, and wind power plants are capital intensive. Because of these fixed costs, project costs have risen and averaged over $1,700 per kilowatt in 2007. Also, higher input prices (steel, cooper, concrete), a shortage of skilled workers, unfavorable currency exchange, and shortages in key wind turbine components and manufacturing capacity have all contributed to the cost increase.

When wind makes up a large part of a power system’s total generating capacity, perhaps 10% to 15% or more, the system must also bear additional costs to provide reliable backup for the wind turbines. This backup capacity is either fossil fuel, nuclear, or other renewable energy (e.g., hydroelectric, geothermal, and biomass).

Reference

CRS Report for Congress, “Wind Power in the United States: Technologies, Economic and Policy Issues,” June 20, 2008.

This is the 2nd in a series of articles on the more subtle aspects of the I2C protocol (which cover TWI and SMBus implementations as well). In the previous article, we discussed the basic hardware and software approaches to implementing support for I2C, as a Master or as a Slave. This article will discuss the Missing Start error condition.

What is a “normal” START?

Per the I2C specification, START is defined as a falling SDA line while SCL remains high. This could theoretically occur at any point during a transmission, and should reset all I2C Slave devices (and Masters as well, in multi-master environments) to be ready to accept a Slave Address transmission. Of course, having this occur under circumstances other than a Bus Idle condition or while awaiting a STOP is likely an error (Unexpected START); this will be discussed in a later article.

What is a “missing” START?

A Missing Start condition could occur if the current bus state permits either a START or a REPEATED START as the next state, but instead sees a falling SCL (with SDA being either high or low, but generally it would be high). The preceding conditions would include: (a) Bus Idle, followed by a START; (b) a NAK having been sent by a Slave device after a Read operation, followed by a Repeated START, or (c) a NAK having been sent by the Master after a Write operation, followed by a Repeated START. In the case of an ACK having been sent by either the Master or a Slave, it is not possible to detect a ‘missing’ START since a START or Repeated START is not required under these circumstances.

By definition, a Bus Idle condition can only be arrived at after a STOP is issued (although at Startup an Idle condition may usually be assumed after the Master is initialized). During Bus Idle, SDA and SCL are defined as both being high. Generating a Missing Start error in this case requires SCL to fall while SDA remains high. The question could be asked, Is it possible to recover valid data even in this scenario? In I2C, a falling SCL indicates that the Transmitter (either Master or Slave) can now advance to the next data bit and update the SDA line. However, there was no previous valid data bit. Slave devices should be expected to ignore SCL activity until a valid START is seen, as the Slave should not accept a Slave Address without a valid START preceding it.

Following a NAK condition, the next bus state should be either a STOP or a Repeated START. If activity is seen on SCL after a NAK, it can be assumed that a Repeated START is missing, since a STOP was not issued (and therefore the bus remains under the control of the current Master). Slave devices likely will not treat the first byte following the NAK as a Slave Address, since a START or Repeated START is required to prepare the Slave device to accept a new address. The question of how the currently-active Slave responds to additional clocking after a NAK is device-dependent, but any data presented should generally be viewed as invalid.

The next article in the series will focus on the Missing Stop error. Thanks for reading!

A fiber optic transmitter is a device that converts an electrical analog or digital signal into a corresponding optical signal. It is one of the components of fiber optics technology that uses long flexible glass-like fibers (optical fibers) for transmitting light signals over long distances. The other two components of the fiber optic transmission system are the fiber optic cable and the optical receiver. Some systems also possess the optical regenerator, which may be essential to boost the degraded light signal (for long distances).

The fiber optic transmitter includes a light emitting diode (LED), or a solid state laser diode, and signal conditioning electronics. Usually, the transmitter processes the signals of wavelengths of 850, 1310, or 1550 nm. LEDs are broadly used for short to moderate transmission distances, while laser diodes are meant for transmitting signals over long distances. Compared to LEDs, laser diodes can couple many times more power to optical fiber.

Separate fiber optic transmitters are available for single-mode fibers and multi-mode fibers. Also, some transmitters allow connecting both single mode and multimode cables in them. Biconic, D4, ESCON, FC, FDDI, LC, Loopback, MTP, MT-RJ, MU, SC, SMA, and ST are some of the common connectors.

Data rate (data bits transmitted per second), transmitter rise time (the time needed for a signal to change from a defined 10% to 90% of full power), wavelength (the output wavelength of the transceiver), spectral width (the spectral width of the output signal), and maximum optical output power are considered to be the important performance specifications while selecting a fiber optic transmitter. The speed of a transmitter is expressed in terms of its rise time.

To specify a fiber optic transmitter, it is necessary to refer to its operating temperature, signal inputs (such as TTL, ECL, CMOS video, and RF), pigtail, focusing lens (improving coupling between the transmitter and the fiber), and stand-alone.

The networks must be transparent to the users. The network and the distributed applications running on it must be as reliable as if they were running on a single computer. In addition, the network must provide self-healing capabilities that can reroute network traffic around broken cables and failed components and be flexible enough to react to business-related changes in its environment.

Local area networks used to be very simple but now they are different structures, at least five computation standards for transmissions, and two standards for the information required to manage the network. Local area networks have become so complex that they require their own operating system.

Networking continues to be the least understood and most critical component in an organization’s Information infra-structure. Most organizations committed to client/server computing agree that linking Local area networks is not the place to skip to save money. The advice is to try not link is compatible Local area networks with different platforms such as hardware, software and operating systems.

Characteristics

1. Interconnected device

2. Backbone networks

3. Desktop high-speed local area network

As Local area networks spread through an organization, bridges and routers are used to connect them. For example, a router could be used to move information among Ethernet, token ring and fiber distributed data interface networks. Users would most likely not realize the full 100MHz of fiber distributed data interface throughout; because the router is manage all connections.

Backbone networks also connect Local area networks, but also provide high-speed transmission and control the flow of data among the various networks. High speed Local area network connects desktop machines directly to the fiber distributed data interface network and, therefore, it has access to the full 100MHz transmission speed. This configuration is designed for high volume, data intensive applications, such as those that transmit graphics information and images.

The two most common Local area networks are Ethernet and International Business Machine’s token ring. Ethernet uses base band coaxial cable or shielded pair wire and can operate at 10MHz. Its protocol is carrier sense multiple-access with collision detection.

This requires a sending device to monitor the network and send the message only it senses the network is not in use. If a collision is detected, the device must stop the transmission and try again when it senses the network is clear.

Token ring uses shielded pair wire or optical cables and can operate at 4 or 16MHz. Its protocol is called token ring. A special signal code, called a token, is passed from stations to station. If a device wants to transmit a message, it wants for the token to come by, takes it of the network, and transmits its message. The token is return to the network after the transmission is completed.

First seen in 1989, the Honda AX 250 soon became a popular motorcycle thanks to its exceptional handling, zippy performance, and rider comfort. Manufactured in Japan and exported as the AX-1, it has almost the same specs as the older American model, the Honda NX250. The changes from the NX 250 are mainly cosmetic, such the distinctive dual headlights and alloy wheels seen in the AX 250. The tried and tested tubular steel double cradle chassis of the NX250 is also found in the AX-1 250 (popularly known as the AX 250).

Powered by a liquid cooled four stroke DOHC single cylinder engine, this Japanese off-road bike could give out 26 hp at 8500 rpm. While these were not the biggest numbers, they were enough to put quite a lot of pep into the 205 pound chassis of the AX 250. This Honda off-roader came with disk brakes for both the front 90/100 19-inch and rear 120/90 16-inch tyres; great for controlled speeding over uneven terrain. The transmission system comprised of 13 front sprocket units coupled with 41 rear sprocket units. For even better control, riders had a 6 speed chain transmission gear box that could take the Honda AX 250 all the way to a top speed of about 85 to 90 mph.

The off-road Honda AX 250 also achieved high marks when it came to rider comfort, thanks to its well-designed suspension and ground clearance of 254 mm. The 37 mm front fork unit had a comfortable 221 mm travel, while the rear suspension unit comprised of a Pro-Link component with 201 mm rear travel; ideal for rough riding! Casual riders also liked the Honda AX 250, thanks to rider-friendly touches such as electric start, dual disk brakes, and worry-free CDI ignition. Depending on the riding conditions, owners have reported pretty good fuel consumption figures, with around 10 miles per gallon.

Manufactured in Japan until 1994, the Honda AX 250 has built up a sizable fan base among the earliest off-road enthusiasts. In fact, a grey market version of the original AX 250 is still available in certain parts of Asia, where it is very popular with tourists keen on touring on the less-than-perfect local roads. The AX 250 continues to be a popular used motorcycle in the UK, thanks to the reliable Honda engine and easily available spare parts. With the right maintenance and quality parts, even a decade-old Honda AX 250 can dazzle spectators and thrill off-road riders.

What exactly is HD radio and how does it compare to Satellite Radio?

You have probably noticed an increasing amount of advertisements promoting this new thing you’ve never heard of before: HD Radio. They say you can hear “undiscovered content” and digital quality audio. You probably even heard the best part of the entire advertisement, “No subscription fee!”

Let me help you learn a little bit about HD Radio. I will try to keep it simple so as to giving you all the information you need with as little technical lingo as possible.

HD is NOT High Definition

First off, you probably have heard of HDTV and if you haven’t heard of it, I’m guessing you live in a cave. HD Radio is not the same thing as HDTV. The HD in HDTV stands for High Definition. Do not mistake this as the same in HD Radio because HD in this context means Hybrid Digital.

However, it delivers much better radio transmission than standard radio signals. Some HD radio stations transmit 5.1 Surround Sound digital audio signals, allowing you to enjoy true concert-like experience. You can be sure that more stations will opt for this mode of transmission in the future.

Digital and Sub-Channels

HD Radio allows various radio stations to broadcast digital information through the FM or AM frequencies. Additionally, these digital transmissions could be sent on numerous sub-channels, allowing about three stations per frequency. This would triple the amount of stations you could potentially listen to on HD Radio. What would it look like on the display, you ask?

Generally, standard AM/FM radios would display the following: FM 104.7

On HD Radios, it would display as: FM 104.7 HD-1 or 104.7 HD-2 (with each HD-X indicating a sub-channel)

As of 2007, the signal quality is reported to be close to CD-quality audio on the FM channels, which is a huge leap in the radio industry. However, it is highly unlikely for AM frequencies to experience this improvement since the AM operates on a much smaller band. Think of it as a hose. A smaller garden hose could not deliver as much water as the fire department’s hose; and unfortunately, AM is that smaller garden hose.

Advancements in Digital Technology

There were reports and complaints in the early stages of HD Radio (2006) of static and interference when tuning in to these HD channels. However, the technology has advanced significantly within the last two years and has improved signal quality and isolation. Don’t worry about quality-loss so much unless you’re on the AM channels.

You may also have heard that the FCC (Federal Communications Commission) begun the process of making obsolete analog radio and television transmissions. What does this mean to you? Well, you can be sure that only improvements will be made. Unfortunately this would mean that most standard AM/FM radios would become obsolete within the next couple of years, possibly forcing you to purchasing a new HD Radio for your vehicle or home.

Comparison to Satellite Radio

Price

Satellite requires a monthly subscription fee ($10-$15/month), activation fee, and cancellation fees if you cancel before your contract is over (if you sign up for the “reduced” contract subscription). To receive Satellite Radio signal (whether Sirius or XM), you would need a special antenna and a satellite-radio that either has a built-in satellite tuner or just plain satellite ready without the built-in tuner (tuner still required and sold separately). Expect to spend anywhere between $150-$300 on equipment alone, depending on what you need (additional tuner or antenna, etc.)*

HD Radio is completely free. You only need to spend money on the receiver itself. Just like Satellite Radio, you could either get a built-in HD Tuner in the in-dash receiver or you could get them separately (in the case where you already own an HD Ready head unit). They’re much more affordable, either way, costing you anywhere between $100-$200 total*.

*Note that these are generalizations of the bare minimum and does not take into consideration additional features you may want with your radio (i.e. Bluetooth, USB support, 3.5mm Aux input, navigation, etc.). They also do not take into consideration labor and parts as each vehicle varies.

Quality and Coverage

The advantage of Satellite Radio is the coverage. You could drive from Los Angeles to New York City listening to the same exact station the whole entire length of the trip. Satellite Radio tends to also specialize in their stations more than HD stations. For instance, there are specific channels for comedy or sports. Satellite Radio is also commercial free since you are after all paying for it.

HD Radio is locally-focused. You tune-in on local metropolitan stations and would not have the same coverage as Satellite as exemplified above. Though HD stations are much more like any typical non-specialized radio stations, it is possible that they may do something similar to Satellite Radio in the future.

Both HD and Satellite Radio do broadcast in digital quality audio. At this point, one does not hold a significant advantage over the other because as with radio-type transmission and reception, it is susceptible to interference and static. Don’t be fooled with the word ‘Satellite’ because of this fact.

If you’re trying to keep up with the current technology but also want to save money, then upgrading to HD Radio isn’t so bad. Most of the well known brands out there like JVC, Eclipse, and Kenwood are producing HD Radio Ready in-dash receivers, forcing you to get additional accessories. Only a handful of companies like Dual and JVC (again) are marketing built-in HD radio tuners.

If you’re pickier with your listening selection, and not too concern about the fees associated with the Satellite Radio, then perhaps you should opt for Sirius or XM Radios. Plenty of popular brands such as Sony, Alpine and Pioneer sell both SAT Ready and built-in Satellite tuner receivers, so you shouldn’t have a problem looking for these.

The choice is yours to make of course. One thing is for certain, however. Digital technology is rapidly advancing and becoming the standard for both audio and video entertainment. Analog (or non-digital) technology will be obsolete. You will have to upgrade to digital eventually. Find out what you like and test them both out. Sometimes the best in the market may not be the best for you. Good luck on your digital revolution!

In the old days, railroad agents had the responsibility of buying up land from the Native Americans for right of ways upon which they could build their tracks. One story tells of a rather shrewd Chief who understood the situation well. This Chief was approached by a railroad agent who offered to buy a particularly poor stretch of land:

Buy my land? . . . Sure, me sell for $50,000, said the Chief.

$50,000! Why that land is no good for planting or pasture. It is just no good for anything! the agent exclaimed.

The Chief grunted, It heep good for railroad. [i]

While this anecdote may seem silly, Kimble County landowners can take from it two important lessons: The first of these lessons is that, like the railroad, the LCRA power transmission lines are probably coming through Kimble County whether we like it or not. While we are only talking about easements and need not fear the total divestment of our ownership rights that the Native Americans went through, a taking is a taking. Public utility companies like the LCRA have the immense power of eminent domain and condemnation bolstering them.

Eminent Domain is common law principal given statutory strength at the State legislature level. It empowers government and quasi-government entities to take any U.S. citizens land for public use. The only real restrictions placed upon this power lie in the Takings Clause of 5th Amendment, which states that private property shall not be taken for public use, without just compensation[ii]

This article is not some sort of call to arms supporting legislative reform. If that is a cause you intend to support, I suggest you take a look at materials provided by the various landownership rights groups or other like-minded organizations around the country.

Rather, what this article hopes to accomplish is to provide helpful tips and background information to Kimble County landowners so that they may better prepare for what is coming and hopefully obtain the best outcome possible.

This brings me to the second lesson we may take from the wise Chief.

Landowners must be aware of and prepared to defend the value of their land. As a property owner, or the “big chief” on your land, can you simply accept what the railroad/LCRA agent thinks the easement over your land is worth? Sure and indeed your life will be simpler that way. However, their offer may not be what you feel entitled to and may be much less than what you could receive with some additional preparation.

Understand that eminent domain/condemnation proceedings are adversarial in nature. This means that even while you may or may not ultimately be able to prevent the installation of the transmission line over your property, you certainly have a voice in determining what the 5th Amendment’s just compensation will be for you. Preparation is key, you are going to be dealing with a team of professionals trained by the LCRA to adhere to a budget and a schedule. Your rights and compensation are NOT their priority.

It is apparent that there is much confusion amongst the public as to how eminent domain/condemnation actions actually work and are going to transpire. Familiarizing yourself with the progression will enable you to better make better decisions when it comes time. The following five steps are a drastically abbreviated schedule of how a normal eminent domain/condemnation matter will likely proceed.

1: If it hasn’t happened already, the LCRA will contact you and request permission to inspect, survey, and appraise your property.

2: An LCRA representative presents to you a valuation of your property and makes an offer.

3: This offer is time sensitive and must be accepted within a specific time frame. If you do not respond or if you reject the offer outright, the LCRA will then likely file their condemnation lawsuit against you.

4: Once this happens the Court selects three special commissioners to conduct a hearing on the matter. The special commissioners will be disinterested property owners that reside in Kimble County. At this hearing, you are able to present evidence to the panel in support of your valuation, cross-examine LCRA appraisers, and generally explain to them why the LCRA valuation is too low. Once the presentation of evidence is conclude, the Commissioners make a determination of value and make that figure their “special award.”

5: This “special award” is not the end game unless you are satisfied with it. If unhappy with the commissioners award, you have a short period of time in which you may object to it and appeal. In this new trial both parties start over from the beginning, and the case proceeds as if the commissioners’ hearing never happened. You will be able to choose whether a judge or a jury decides your case.

As you can see, it’s really all just about money. The steps I have outlined are your opportunities to have a say in how much you are going to receive. Essentially, you have three primary options: come to negotiated agreement with LCRA, accept the special commissioners’ award, or have a judge or jury decide how much you should receive.

Make no mistake; property valuation can be very complicated in the eminent domain context. Perhaps you have sold a property in the past; maybe you even contested the tax valuation of your own home. The appraisals and valuations in these situations are very simple calculations compared to those in used condemnation matters. Property valuation evidence in condemnation proceedings must adhere to and reflect a body of condemnation law hewn out over decades in Texas Appellate Courts. It would be wise to seek professional assistance early in the game.

Fundamentally, in valuating easements in the transmission line context, we are really actually talking about de-valuation. How much less is my property worth now that there are power lines running through it, and is that amount of devaluation also the amount of money I could be compensated with and be happy? To set the tone, throw out some actual numbers, and give you a general idea of what sort of devaluation I am referring to, consider the following:

In 1997, the LCRA actually commissioned a study to figure out just how much that its power transmission lines affected the value of the properties they cross.[iii] The geographical area studied was around Georgetown, Texas. This study was completed by an appraiser who the LCRA had hired to do all of the appraisal work on an easement acquisition project very similar to the one proposed for Kimble County. The only difference is that this study was done for a much smaller 138 Kv transmission line than the double circuit 345 Kv lattice tower we are facing today.

In this study, completed by an appraiser paid by LCRA, undeniable devaluation was found. It concluded that a transmission line easement has less than a 10% impact on price, and in most instances, less than a 5% impact on price.[v] Importantly, this is a possible 10% overall impact on price for the entire property.[vi] Put simply, if you owned targeted land around Georgetown around the millennium, the LCRA turned your $500,000.00 property into a $450,000.00. – $475,000.00 property.

For the land directly underneath and near the line, the study concluded:

“It is concluded that the area located within an electric transmission line easement has a 90% diminution in value due to the presence of the easement. [and] [i]t is concluded that an area 200 feet wide adjoining the proposed easement has some diminished value. The extent of the diminished value can be dependent on various factors which would include the location of the easement relative to the whole tract, and the physical characteristics of the remainder.[vii]

This is, of course, is ten year old data from a single source that only considers strict real estate values. Additionally, this study was conducted for much smaller transmission lines; and should be considered only as a point of reference.

Much has changed since 1997, but is my opinion that it has changed in favor of the landowner rather than the LCRA. To arrive at a more fair devaluation figure, one

Optical WDM (Wavelength Division Multiplexing) networks are networks that deploy optical WDM fiber links where each fiber link carries multiple wavelength channels. An All Optical Network (AON) is an optical WDM network which provides end-to-end optical paths by using all optical nodes that allow optical signal to stay in optical domain without conversion to electrical signal. AONs are usually optical circuit-switched networks where circuits are switched by intermediate nodes in the granularity of a wavelength channel. Hence a circuit-switched AON is also called a wavelength routing network where optical circuits are equivalent to wavelength channels.

A wavelength routing network consists of optical cross-connects (OXC) and optical add/drop multiplexers (OADM) interconnected by WDM fibers. Transmission of data over this optical network is done using optical circuit-switching connections, known as lightpaths. An OXC is an N x N optical switch with N input fibers and N output fibers with each fiber carries W wavelengths. The OXC can optically switch all of the incoming wavelengths of its input fibers to the outgoing wavelengths of its output fibers. An OADM can terminate the signals on a number of wavelengths and inserts new signals into these wavelengths. The remaining wavelengths pass through the OADM transparently.

In order for a user (router A) to transmit data to a destination user (router B), a circuit-switching connection is established by using a wavelength on each hop along the connection path. This unidirectional optical path is called a lightpath and the node between each hop is either an OXC or an OADM. A separate lightpath has to be established using different fibers to set up transmission in the opposite direction. To satisfy the wavelength continuity constraint, the same wavelength is used on every hop along the lightpath. If a lightpath is blocked because the required wavelength is unavailable, a converter in an OXC can transform the optical signal transmitted from one wavelength to another wavelength.

Since the bandwidth of a wavelength is often much larger than that requires by a single client, traffic glooming is used to allow the bandwidth of a lightpath to be shared by many clients. The bandwidth of a lightpath is divided into subrate units; clients can request one or more subrate units to carry traffic streams at lower rates. For example, information is transmitted over an optical network using SONET (Synchronous Optical Network) framing with a transmission rate of OC-48 (2.488 Gbps). A lightpath is established from OXC1 to OXC3 through OXC2 using wavelength w, the subrate unit available on this lightpath is OC-3 (155 Mbps). A user on OXC1 can request any integer number of OC-3 subrate units up to a total of 16 to transmit data to another user on OXC3. A network operator can use traffic-groomed lightpaths to provide subrate transport services to the users by adding a virtual network to the optical network.

Information on a lightpath is typically transmitted using SONET framing. In the future, the information transmitted over optical network will use the new ITU-T G.709 standard, known as digital wrapper. In ITU-T, an optical network is referred to as the optical transport network (OTN). The following are some of the features of G.709 standard:

1) The standard permits transmission of different types of traffic: IP packets and gigabit Ethernet frames using Generic Framing Procedure (GFP), ATM cells and SONET/SDH synchronous data.

2) It supports three bit rate granularities: 2.488 Gbps, 9.95 Gbps and 39.81 Gbps.

3) It provides capabilities to monitor a connection on an end-to-end basis over several carriers, as well as over a single carrier.

4) G.709 uses Forward Error Correction (FEC) to detect and correct bit errors caused by physical impairments in the transmission links.

Lightpath can either be static or dynamic. Static lightpaths are established using network management procedures and may remain up for a long time. Virtual Private Networks (VPN) can be set up using static lightpaths. Dynamic lightpaths are established in real time using signaling protocols, such as IETF’s GMPLS (Generalized Multi-Protocol Label Switching) and UNI (User Network Interface) proposed by Optical Internetworking Forum (OIF). GMPLS is an extension of MPLS and was designed to apply MPLS label switching techniques to Time Division Multiplexing (TDM) networks and wavelength routing networks, in addition to packet switching networks. The OIF UNI specifies signaling procedures for clients to automatically create, delete and query a connection over wavelength routing network. The UNI signaling is implemented by extending the label distribution protocols, LDP and RSVP-TE.