Role Of The Media During The Vietnam War - 2179 Words

Tan Oguz Instructor: Arjun Subrahmanyan HIST 386C 11 December 2014 Final Paper Role of the Media in the Vietnam War Vietnam War is a war that mainly differentiates from any other war in the history of the modern warfare due to the fact that the first time in history the media was able to act without restrictions and had the opportunity to film and record the war from the frontline of the combat zone. Besides the political and military decisions taken at the wartime, media had a impact on changing destiny of the war. In this essay, in order to show the impact of the media on the war, I will try to examine some of the key events of the Vietnam War, such as the Tet-Offensive, and My Lai Massacre. Were there any misconceptions presented by the media about the war? Was media responsible of the US loss in Vietnam? Is the power of media exaggerated at the time of the war? Throughout the essay, these questions will try to be answered in the contexts of specific events. Before the insertion of ground troops in Vietnam, much of the concern in the media had been favoured to the political tactics of reinforcing a non-communist (democratic) government in South Vietnam. After the war changed its direction to heavy ground batlle, a change in coverage also eventuated that the media were more concerned and interested in military conjuncture (Wyatt 1995). By becoming more interested in military aspects of the war, the media became more engaged in actual fight scenes and brutality of theShow MoreRelatedEssay on The Role of Media During the Vietnam War1903 Words   |  8 PagesDuring the Vietnam War, Americans were greatly influenced by the extensive media coverage of the war. Before the 1960’s and the intensification of the war, public news coverage of military action was constrained heavily by the government and was directed by Government policy. The Vietnam War uniquely altered the perception of war in the eyes of American citizens by bringing the war into their homes. The Vietnam War was the first U.S uncensored war resulting in the release of graphic images and unalteredRead MoreThe Effect of Mass Media on Americans during the Vietnam War Essay1114 Words   |  5 Pagesof Mass Media on Americans during the Vietnam War When the war initially began, Dean Rusk, US Secretary of State, pointed out that: This was the first struggle fought on television in everybodys living room every day... whether ordinary people can sustain a war effort under that kind of daily hammering is a very large question. The us administration, unlike most governments at war, made no official attempt to censure the reporting in the Vietnam war. Every Read MoreMedia Coverage On The Vietnam War1549 Words   |  7 PagesThe Vietnam War introduced many new forms of technology on and off of the battlefield. Increased weaponry helped shape the outcome of the war, but media coverage also played a large role in representing the news and opinions of the war. Viet Thanh Nguyen’s The Sympathizer helps illustrate how the media influences and spreads the opinions of the people during the Vietnam War. The war media, which includes newspapers, movies, and most importantly television, caters towards its audience. What the mediaRead More The Impact of the Media on the Vietnam War Essay1710 Words   |  7 PagesThe Impact of the Media on the Vietnam War This essay will discuss to what degree the media can be blamed for the United States’ loss in the Vietnam conflict ending 1975. It will be based predominantly on key written resources on the subject, but it will also contain - by means of an interview - certain first-hand observations from a Vietnam War veteran. For the sake of conciseness, and in order to focus the bulk of the content on the main topic, this essay will make certain assumptionsRead MoreThe Media and the Military in the Vietnam War1593 Words   |  6 PagesThe media and Military The War in Vietnam was the first real â€Å"television† war, meaning it was the first conflict where the U.S. military found itself attempting to control a media which was not fully supportive of the country’s involvement. (79) It was also the first â€Å"open† conflict where the media was deployed in force without restriction. (79) The media saw a need to cater to those who opposed the war for the first time. The conflict was taking place in a remote area, and apart from conscriptionRead MoreMedia Coverage Of The Vietnam War1257 Words   |  6 Pagesin the traditional sense. They fight with audio and video, instead. (Rewrite Hook) This was live coverage of the Vietnam War, a long, bloody, unforgotten, and unappreciated war. Once these horrifying images were cast onto American screens, United States would find itself covered in ruins. Ruins that would cost years and years to rebuild. (Fix Transition) Media coverage of the Vietnam War ignited a new era of journalism and served as a driving force in the public’s perception of United States involvementRead MoreThe Problem With Vietnam Essays1660 Words   |  7 PagesThe Problem With Vietnam Wartime in the United States has always placed pressure on the government and the citizens of the country to provide support by whatever means to the situation. During World War II, that support was propagated by the government in the form of censorship and a strategic public relations plan to maintain the public opinion in favor of the cause. Glorification of Americas involvement in the war helped America maintain the image of a cause worth fighting for. TechnologyRead MoreU.s Propaganda On Vietnam War1355 Words   |  6 Pages U.S propaganda in Vietnam War In the need of human resources, the U.S government in the 3rd quarter of the 20th century has started mobilizing young men into navy and military troops. This mobilization was preceded with heavy amount of propaganda that used big variety of different motives to recruit as many people as possible and to stop the deserters that tried to flee to the country. The motives used in propaganda ranged from hateful to nationalistic. When thinking of power, most people thinkRead MoreThe Vietnam War And Its Horrors1130 Words   |  5 Pages The Vietnam War and its horrors came into the living rooms of people through from news reports through television. This war was the first war to issue full freedom to the press. There was a huge response to what people saw in a negative way. Many people thought the war should not have been televised. According to â€Å"U.S. at War: A History of Shame†, it was until 1965 that the Vietnam War became a big story on television. Journalism coverage of thi s war using television had a huge effect on the peopleRead MoreThe Battle Of The Vietnam War Essay1431 Words   |  6 Pagesdiscussion of the Vietnam War was never far from people’s minds. This war would serve as an introduction to what war was to the home front. It was in the homes of America where so many had been previously sheltered from the realities of war. During previous conflicts, there had been a military censorship on all media that pertained to war. This would not be the case in Vietnam, it would be completely uncensored. The ability for reporters to provide a commentary on the war without censorship

Busy Parents The Real Cause Childhood Obesity - 1201 Words

In the article â€Å"Busy Parents: The Real Cause of Childhood Obesity,† the author points out the fact the as childhood obesity has tripled over the past thirty years we continue to blame the packaged food industry or what is called a sedentary lifestyle; a lifestyle with no or irregular physical activity. Author, Suzanne Venker states that those points do matter but it wouldn’t matter as much if parents were home to have a certain control on their children’s lives. The author came to the conclusion that once more and more mothers began to leave home and enter the workforce it took a big impact on the children’s eating habits. Even the first lady, Michelle Obama admits to this conclusion as she evolves her â€Å"Let’s Move Campaign.† In the next article â€Å"Childhood Obesity: Do Parents Have the Right to Point Finger?† author, Isabella Gonzalez focusing on the view that obesity can be simply caused by the influence on the people who are around them the most; the parents and also simply depression, loss of elf-esteem, and anxiety. With these points it shows that this epidemic can not only be caused by what the community meaning the lack of physical education within the school systems or even how much cheaper fast food is. This author goes on explaining hw fast food companies have nutrition labeling and the point where an individual is out of hand is when ne intakes too much of it. â€Å"These companies do not have a knife to our throats forcing us to eat their food, it is up to the consumer†Show MoreRelatedChildhood Obesity Essay examples1472 Words   |  6 PagesAmerica childhood obesity was rarely a topic of conversation. A survey done in the early 1970s showed that 6.1% of children between the ages 12 and 19 were overweight. Eight years later the same survey was done and 17.4% were considered overweight (Iannelli). â€Å"Childhood obesity epidemic in America is now a confirmed fact since the number of overweight or obese children has more than tripled during the last 30 years† (Childhood Obesity Epidemic). â€Å"Over the last 20 years, the prevalence of obesity in childrenRead MoreObesity Is A Major Problem1234 Words   |  5 Pagesfour decades, the rate of obesity in America has been on the increasing end; two out of three Americans are either obese or overweight. The obesity epidemic has become a major problem in the United States which caused many serious effects on individual and society. It is an indiscriminate problem that negatively affect everyone from adults to children; which is a significant threat to the health of humanity that needs to be eliminated. First, we need to know what obesity is. According to OxfordRead MoreParents, Schools, and Society Must Fight Childhood Obesity Essay examples1183 Words   |  5 Pagesâ€Å"Childhood obesity has more than tripled in the past 30 years† (Adolescent and School Health), this is according to a report from the Centers for Disease Control. Obesity has become a national epidemic. This problem is not exclusive to the United States. The obesity rate has been rising all over the world. Many are confused by what it means to be obese. Obesity is having an excessive amount of body fat or a high BMI, body mass index, not just being overweight. The real concern here is the young ageRead MoreChildhood Obesity : An Epidemic1036 Words   |  5 PagesRainsu Kumbhani All About Childhood Obesity Childhood obesity is an epidemic in U.S. In the year of 2012, about â€Å"one third of children and adolescents were overweight or obese.† Also, percentages of childhood obesity have increased by over ten percent in the last thirty years in children and adolescents (Childhood Obesity Facts 2015). These statistics are shocking, and many people are concerned for the health of their children. This medical condition, as defined by Mayo Clinic, leads to seriousRead MoreEating Food At The End Of A Day974 Words   |  4 Pagesneed to eat their salad first for example. I am a mother of three, with a full time job, assist school full time as well, this on top of other responsibilities that come with having a family, so I know how hard this can be and empathize with all the parents that decide to eat out most nights, because sometimes when I am tired I wish I could afford doing that. However, when we opt on not cooking for the day, and we buy our children’s meals at fast food p laces, are we making healthy decisions for themRead MoreChild Diabetes Essay1142 Words   |  5 PagesIn today’s world, parents have an abundance of worries when it comes to their children. Drugs, bad grades, and pre marital sex are just some things that may plague a parent with sleepless nights. But even on the worst of those nights of worry, most parents can’t imagine that their child could face an illness. Not just a runny nose or seasonal flu, but an illness that would affect their child throughout his or her entire life. Diabetes is a disease without a cure, and one that more, and more childrenRead MoreThe Effects Of Television On Children And Adolescents1449 Words   |  6 PagesBushman s research has been found that when we view violent programming we store in memory, a perceptual and cognitive representation of the event. This means we can draw it up in our thoughts and also visually. His studies show that when put in a real situation that is similar to the memory we have stored, that memory is activated and the memory script becomes available to use. This especially fits with 8-year-old boys who show signs of aggression at a later age with the memories pulled up and activatedRead MoreObesity Statistics And Rankings : Obesity1442 Words   |  6 PagesObesity Statistics and Rankings The first national survey conducted in United States was in 1963. Many of the studies have suggested that child obesity epidemic is recent and unexpected. Over the last three decades, obesity rates have tripled in the U.S. One out of six children is obese and a one out of three child is overweight. The United States is ranked number one in the world. There has been some control and steadiness in the child obesity rates since 2008, but there are someRead MoreThe Effects Of Television On Children And Adolescents1446 Words   |  6 PagesBushman s research has been found that when we view violent programming, we store in memory, a perceptual and cognitive representation of the event. This means we can draw it up in our thoughts and also visually. His studies show that when put in a real situation that is similar to the memory we have stored, that memory is activated and the memory script becomes available to use. This is especially fitting with 8-year-old boys who show sig ns of aggression at a later age with the memories pulled upRead MoreThe Effects Of Television On Children And Adolescents1446 Words   |  6 PagesBushman s research has been found that when we view violent programming, we store in memory, a perceptual and cognitive representation of the event. This means we can draw it up in our thoughts and also visually. His studies show that when put in a real situation that is similar to the memory we have stored, that memory is activated and the memory script becomes available to use. This is especially fitting with 8-year-old boys who show signs of aggression at a later age with the memories pulled up

Digital Subscriber Line Free Essays

string(381) " telephone lines may attenuate signals at 1 MHz \(the outer edge of the band used by ADSL\) by as much as 90 dB, forcing analog sections of ADSL modems to work very hard to realize large dynamic ranges, separate channels, and Internetworking Technologies Handbook 1-58705-001-3 21-3 Chapter 21 Asymmetric Digital Subscriber Line Digital Subscriber Line maintain low noise figures\." C H A P T E R Chapter Goals †¢ †¢ †¢ †¢ †¢ Identify and discuss different types of digital subscriber line (DSL) technologies. Discuss the benefits of using xDSL technologies. Explain how ASDL works. We will write a custom essay sample on Digital Subscriber Line or any similar topic only for you Order Now Explain the basic concepts of signaling and modulation. Discuss additional DSL technologies (SDSL, HDSL, HDSL-2, G. SHDSL, IDSL, and VDSL). Digital Subscriber Line Introduction Digital Subscriber Line (DSL) technology is a modem technology that uses existing twisted-pair telephone lines to transport high-bandwidth data, such as multimedia and video, to service subscribers. The term xDSL covers a number of similar yet competing forms of DSL technologies, including ADSL, SDSL, HDSL, HDSL-2, G. SHDL, IDSL, and VDSL. xDSL is drawing significant attention from implementers and service providers because it promises to deliver high-bandwidth data rates to dispersed locations with relatively small changes to the existing telco infrastructure. xDSL services are dedicated, point-to-point, public network access over twisted-pair copper wire on the local loop (last mile) between a network service provider’s (NSP) central office and the customer site, or on local loops created either intrabuilding or intracampus. Currently, most DSL deployments are ADSL, mainly delivered to residential customers. This chapter focus mainly on defining ADSL. Asymmetric Digital Subscriber Line Asymmetric Digital Subscriber Line (ADSL) technology is asymmetric. It allows more bandwidth downstream—from an NSP’s central office to the customer site—than upstream from the subscriber to the central office. This asymmetry, combined with always-on access (which eliminates call setup), makes ADSL ideal for Internet/intranet surfing, video-on-demand, and remote LAN access. Users of these applications typically download much more information than they send. Internetworking Technologies Handbook 1-58705-001-3 21-1 Chapter 21 Asymmetric Digital Subscriber Line Digital Subscriber Line ADSL transmits more than 6 Mbps to a subscriber and as much as 640 kbps more in both directions (shown in Figure 21-1). Such rates expand existing access capacity by a factor of 50 or more without new cabling. ADSL can literally transform the existing public information network from one limited to voice, text, and low-resolution graphics to a powerful, ubiquitous system capable of bringing multimedia, including full-motion video, to every home this century. Figure 21-1 The Components of an ADSL Network Include a Telco and a CPE Core network Existing copper Server ADSL ADSL 1. 5 to 9 Mbps 16 to 640 kbps Internet ADSL connection ADSL will play a crucial role over the next decade or more as telephone companies enter new markets for delivering information in video and multimedia formats. New broadband cabling will take decades to reach all prospective subscribers. Success of these new services depends on reaching as many subscribers as possible during the first few years. By bringing movies, television, video catalogs, remote CD-ROMs, corporate LANs, and the Internet into homes and small businesses, ADSL will make these markets viable and profitable for telephone companies and application suppliers alike. ADSL Capabilities An ADSL circuit connects an ADSL modem on each end of a twisted-pair telephone line, creating three information channels: a high-speed downstream channel, a medium-speed duplex channel, and a basic telephone service channel. The basic telephone service channel is split off from the digital modem by filters, thus guaranteeing uninterrupted basic telephone service, even if ADSL fails. The high-speed channel ranges from 1. 5 to 9 Mbps, and duplex rates range from 16 to 640 kbps. Each channel can be submultiplexed to form multiple lower-rate channels. ADSL modems provide data rates consistent with North American T1 1. 544 Mbps and European E1 2. 048 Mbps digital hierarchies (see Figure 21-2), and can be purchased with various speed ranges and capabilities. The minimum configuration provides 1. 5 or 2. 0 Mbps downstream and a 16-kbps duplex channel; others provide rates of 6. 1 Mbps and 64 kbps for duplex. Products with downstream rates up to 8 Mbps and duplex rates up to 640 kbps are available today. ADSL modems accommodate Asynchronous Transfer Mode (ATM) transport with variable rates and compensation for ATM overhead, as well as IP protocols. Internetworking Technologies Handbook 21-2 1-58705-001-3 Chapter 21 Digital Subscriber Line Asymmetric Digital Subscriber Line Figure 21-2 This Chart Shows the Speeds for Downstream Bearer and Duplex Bearer Channels Downstream bearer channels n x 1. 536 Mbps 1. 536 Mbps 3. 072 Mbps 4. 608 Mbps 6. 144 Mbps 2. 048 Mbps 4. 096 Mbps x 2. 048 Mbps Duplex bearer channels C channel Optional channels 16 Kbps 64 Kbps 160 Kbps 384 Kbps 544 Kbps 576 Kbps Downstream data rates depend on a number of factors, including the length of the copper line, its wire gauge, the presence of bridged taps, and cross-coupled interference. Line attenuation increases with line length and frequency, and decreases as wire diameter increases. Ignoring bridged taps, ADSL perfo rms as shown in Table 21-1. Table 21-1 Claimed ADSL Physical-Media Performance Data Rate (Mbps) 1. 5 or 2 1. 5 or 2 6. 1 6. 1 Wire Gauge (AWG) 24 26 24 26 Distance (feet) 18,000 15,000 12,000 9,000 Wire Size (mm) 0. 5 0. 4 0. 5 0. 4 Distance (km) 5. 5 4. 6 3. 7 2. 7 Although the measure varies from telco to telco, these capabilities can cover up to 95 percent of a loop plant, depending on the desired data rate. Customers beyond these distances can be reached with fiber-based digital loop carrier (DLC) systems. As these DLC systems become commercially available, telephone companies can offer virtually ubiquitous access in a relatively short time. Many applications envisioned for ADSL involve digital compressed video. As a real-time signal, digital video cannot use link- or network-level error control procedures commonly found in data communications systems. Therefore, ADSL modems incorporate forward error correction that dramatically reduces errors caused by impulse noise. Error correction on a symbol-by-symbol basis also reduces errors caused by continuous noise coupled into a line. ADSL Technology ADSL depends on advanced digital signal processing and creative algorithms to squeeze so much information through twisted-pair telephone lines. In addition, many advances have been required in transformers, analog filters, and analog/digital (A/D) converters. Long telephone lines may attenuate signals at 1 MHz (the outer edge of the band used by ADSL) by as much as 90 dB, forcing analog sections of ADSL modems to work very hard to realize large dynamic ranges, separate channels, and Internetworking Technologies Handbook 1-58705-001-3 21-3 Chapter 21 Asymmetric Digital Subscriber Line Digital Subscriber Line maintain low noise figures. You read "Digital Subscriber Line" in category "Papers" On the outside, ADSL looks simple—transparent synchronous data pipes at various data rates over ordinary telephone lines. The inside, where all the transistors work, is a miracle of modern technology. Figure 21-3 displays the ADSL transceiver-network end. Figure 21-3 This Diagram Provides an Overview of the Devices That Make Up the ADSL Transceiver-Network End of the Topology Downstream channel(s) Duplex channel(s) Mux Error control XMTR D/A and A/D Line coupler Channel separation (FDM or ECH) Basic telephone service splitter Line Demux Duplex channel(s) Error control RCVR Basic telephone service ADSL transceiver–network end (Premises end is mirror image) To create multiple channels, ADSL modems divide the available bandwidth of a telephone line in one of two ways: frequency-division multiplexing (FDM) or echo cancellation, as shown in Figure 21-4. FDM assigns one band for upstream data and another band for downstream data. The downstream path is then divided by time-division multiplexing into one or more high-speed channels and one or more low-speed channels. The upstream path is also multiplexed into corresponding low-speed channels. Echo cancellation assigns the upstream band to overlap the downstream, and separates the two by means of local echo cancellation, a technique well known in V. 32 and V. 34 modems. With either technique, ADSL splits off a 4-kHz region for basic telephone service at the DC end of the band. Internetworking Technologies Handbook 21-4 1-58705-001-3 Chapter 21 Digital Subscriber Line Signaling and Modulation Figure 21-4 ADSL Uses FDM and Echo Cancellation to Divide the Available Bandwidth for Services FDM Upstream Basic telephone service Downstream Frequency Echo cancellation Upstream Basic telephone service Downstream 1 Mhz Frequency 1 Mhz An ADSL modem organizes the aggregate data stream created by multiplexing downstream channels, duplex channels, and maintenance channels together into blocks, and it attaches an error correction code to each block. The receiver then corrects errors that occur during transmission, up to the limits implied by the code and the block length. At the user’s option, the unit also can create superblocks by interleaving data within subblocks; this allows the receiver to correct any combination of errors within a specific span of bits. This, in turn, allows for effective transmission of both data and video signals. Signaling and Modulation This section includes the following: †¢ †¢ CAP and DMT Modulated ADSL ADSL Standards and Associations CAP and DMT Modulated ADSL DMT and CAP are line-coding methods for modulating the electrical signals sent over the copper wire in the local loop. Carrierless Amplitude and Phase (CAP) is a common line-coding method. CAP is a well-understood technology because of its similarity with QAM. Although CAP is well-understood and relatively inexpensive, some argue that it is difficult to scale because it is a single-carrier modulation technique and is susceptible to narrowband interference. DMT uses multiple carriers. At this point, DMT is capable of more speed than CAP. This is one reason that the ANSI committee T1E1. accorded it standards status in document T1. 413. This standard calls for 256 subbands of 4 KHz each, thereby occupying 1. 024 GHz. Each subband can be modulated with QAM 64 for clean subbands, down to QPSK. If each of the subbands can support QAM-64 modulation, then the forward channel supports 6. 1 Mbps. On the return path are 32 subbands, with a potential for 1. 5 Mbps. Internetworking Technologies H andbook 1-58705-001-3 21-5 Chapter 21 Signaling and Modulation Digital Subscriber Line CAP and DMT Compared CAP is a single-carrier technique that uses a wide passband. DMT is a multiple-carrier technique that uses many narrowband channels. The two have a number of engineering differences, even though, ultimately, they can offer similar service to the network layers discussed previously. Adaptive Equalization Adaptive equalizers are amplifiers that shape frequency response to compensate for attenuation and phase error. Adaptive equalization requires that the modems learn line characteristics and do so by sending probes and looking at the return signals. The equalizer then knows how it must amplify signals to get a nice, flat frequency response. The greater the dynamic range, the more complex the equalization. ADSL requires 50 dB of dynamic range, complicating adaptive equalization. Only with recent advances in digital signal processing (number crunching) has it become possible to have such equalization in relatively small packaging. Adaptive equalization is required for CAP because noise characteristics vary significantly across the frequency passband. Adaptive equalization is not needed for DMT because noise characteristics do not vary across any given 4-KHz subband. A major issue in comparing DMT with CAP is determining the point at which the complexity of adaptive equalization surpasses the complexity of DMT’s multiple Fourier transform calculations. This is determined by further implementation experience. Power Consumption Although DMT clearly scales and does not need adaptive equalization, other factors must be considered. First, with 256 channels, DMT has a disadvantage regarding power consumption (and, therefore, cost) when compared with CAP. DMT has a high peak-to-average power ratio because the multiple carriers can constructively interfere to yield a strong signal. DMT has higher computational requirements, resulting in more transistors than the transceiver chips. Numbers are mostly proprietary at this point, but it is estimated that a single transceiver will consume 5 W of power, even with further advances. Power consumption is important because hundreds or thousands (as carriers dearly hope) of transceivers might be at the central office, or CEV. This would require much more heat dissipation than CAP requires. Latency Another issue for DMT is that latencies are somewhat higher than with CAP (15). Because each subband uses only 4 KHz, no bit can travel faster than permitted by a QAM-64. The trade-off between throughput and latency is a historical one in data communications and has normally been settled in the marketplace. Speed DMT appears to have the speed advantage over CAP. Because narrow carriers have relatively few equalization problems, more aggressive modulation techniques can be used on each channel. For CAP to achieve comparable bit rates, it might be necessary to use more bandwidth, far beyond 1 MHz. This creates new problems associated with high frequencies on wires and would reduce CAP’s current advantage in power consumption. Internetworking Technologies Handbook 21-6 1-58705-001-3 Chapter 21 Digital Subscriber Line Additional DSL Technologies ADSL Standards and Associations The American National Standards Institute (ANSI) Working Group T1E1. 4 recently approved an ADSL standard at rates up to 6. 1 Mbps (DMT/ANSI Standard T1. 413). The European Technical Standards Institute (ETSI) contributed an annex to T1. 413 to reflect European requirements. T1. 413 currently embodies a single terminal interface at the premises end. Issue II expands the standard to include a multiplexed interface at the premises end, protocols for configuration and network management, and other improvements. The ATM Forum and the Digital Audio-Visual Council (DAVIC) have both recognized ADSL as a physical layer transmission protocol for UTP media. Additional DSL Technologies This section discusses the following DSL technologies: †¢ †¢ †¢ †¢ †¢ †¢ SDSL HDSL HDSL-2 G. SHDSL ISDN Digital Subscriber Line (DSL) VDSL SDSL Symmetric Digital Subscriber Line (SDSL) is a rate-adaptive version of HDSL and, like HDSL, is symmetric. It allows equal bandwidth downstream from an NSP’s central office to the customer site as upstream from the subscriber to the central office. SDSL supports data only on a single line and does not support analog calls. SDSL uses 2B1Q line coding and can transmit up to 1. 54 Mbps to and from a subscriber, or can be configured to offer a variable range of bandwidth up to 1. 45 Mbps. The symmetry that SDSL offers, combined with always-on access (which eliminates call setup), makes it a favorable WAN technology for small to medium businesses and branch offices, and can be an affordable alternative to dedicated leased lines and Frame Relay services. Because traffic is symmetrical, file transfer, web hosting, and distance-learning applications can effectively be implemented with SDSL. HDSL Originally developed by Bellcore, high bit-rate DSL (HDSL)/T1/E1 technologies have been standardized by ANSI in the United States and by ETSI in Europe. The ANSI standard covers two-pair T1 transmission, with a data rate of 784 kbps on each twisted pair. ETSI standards exist both for a two-pair E1 system, with each pair carrying 1168 kbps, and a three-pair E1 system, with 784 kbps on each twisted pair. HDSL became popular because it is a better way of provisioning T1 or E1 over twisted-pair copper lines than the long-used technique known as Alternative Mark Inversion (AMI). HDSL uses less bandwidth and requires no repeaters up to the CSA range. By using adaptive line equalization and 2B1Q modulation, HDSL transmits 1. 544 Mbps or 2. 048 Mbps in bandwidth ranging from 80ntrast to the 1. 5 MHz required by AMI. (AMI is still the encoding protocol used for the majority of T1. ) Internetworking Technologies Handbook 1-58705-001-3 21-7 Chapter 21 Additional DSL Technologies Digital Subscriber Line T1 service can be installed in a day for less than $1,000 by installing HDSL modems at each end of the line. Installation via AMI costs much more and takes more time because of the requirement to add repeaters between the subscriber and the CO. Depending on the length of the line, the cost to add repeaters for AMI could be up to $5,000 and could take more than a week. HDSL is heavily used in cellular telephone buildouts. Traffic from the base station is backhauled to the CO using HDSL in more than 50 percent of installations. Currently, the vast majority of new T1 lines are provisioned with HDSL. However, because of the embedded base of AMI, less than 30 percent of existing T1 lines are provisioned with HDSL. HDSL does have drawbacks. First, no provision exists for analog voice because it uses the voice band. Second, ADSL achieves better speeds than HDSL because ADSL’s asymmetry deliberately keeps the crosstalk at one end of the line. Symmetric systems such as HDSL have crosstalk at both ends. HDSL-2 HDSL-2 is an emerging standard and a promising alternative to HDSL. The intention is to offer a symmetric service at T1 speeds using a single-wire pair rather than two pairs. This will enable it to operate for a larger potential audience. It will require more aggressive modulation, shorter distances (about 10,000 feet), and better phone lines. Much of the SDSL equipment in the market today uses the 2B1Q line code developed for Integrated Services Digital Network. The Bell companies have insisted that using this SDSL at speeds higher than 768 kbps can cause interference with voice and other services that are offered on copper wire within the same wire bundle. The biggest advantage of HDSL-2, which was developed to serve as a standard by which different vendors’ equipment could interoperate, is that it is designed not to interfere with other services. However, HDSL-2 is full rate only, offering services only at 1. 5 Mbps. G. SHDSL G. SHDSL is a standards-based, multirate version of HDSL-2 and offers symmetrical service. The advantage of HDSL-2, which was developed to serve as a standard by which different vendors’ equipment could interoperate, is that it is designed not to interfere with other services. However, the HDSL-2 standard addresses only services at 1. 5 Mbps. Multirate HDSL-2 is part of Issue 2 of the standard known as G. SHDSL, and is ratified by the ITU. G. SHDSL builds upon the benefits of HDSL-2 by offering symmetrical rates of 2. 3 Mbps. ISDN Digital Subscriber Line ISDN digital subscriber line (IDSL) is a cross between ISDN and xDSL. It is like ISDN in that it uses a single-wire pair to transmit full-duplex data at 128 kbps and at distances of up to RRD range. Like ISDN, IDSL uses a 2B1Q line code to enable transparent operation through the ISDN â€Å"U† interface. Finally, the user continues to use existing CPE (ISDN BRI terminal adapters, bridges, and routers) to make the CO connections. The big difference is from the carrier’s point-of-view. Unlike ISDN, ISDL does not connect through the voice switch. A new piece of data communications equipment terminates the ISDL connection and shuts it off to a router or data switch. This is a key feature because the overloading of central office voice switches by data users is a growing problem for telcos. Internetworking Technologies Handbook 21-8 1-58705-001-3 Chapter 21 Digital Subscriber Line Summary The limitation of ISDL is that the customer no longer has access to ISDN signaling or voice services. But for Internet service providers, who do not provide a public voice service, ISDL is an interesting way of using POTS dial service to offer higher-speed Internet access, targeting the embedded base of more than five million ISDN users as an initial market. VDSL Very-High-Data-Rate Digital Subscriber Line (VDSL) transmits high-speed data over short reaches of twisted-pair copper telephone lines, with a range of speeds depending on actual line length. The maximum downstream rate under consideration is between 51 and 55 Mbps over lines up to 1000 feet (300 m) in length. Downstream speeds as low as 13 Mbps over lengths beyond 4000 feet (1500 m) are also common. Upstream rates in early models will be asymmetric, just like ADSL, at speeds from 1. 6 to 2. 3 Mbps. Both data channels will be separated in frequency from bands used for basic telephone service and Integrated Services Digital Network (ISDN), enabling service providers to overlay VDSL on existing services. Currently, the two high-speed channels are also separated in frequency. As needs arise for higher-speed upstream channels or symmetric rates, VDSL systems may need to use echo cancellation. Summary ASDL technology is asymmetric, allowing more bandwidth for downstream than upstream data flow. This asymmetric technology combined with always-on access makes ASDL ideal for users who typically download much more data than they send. An ASDL modem is connected to both ends of a twisted-pair telephone line to create three information channels: a high-speed downstream channel, a medium-speed duplex channel, and a basic telephone service channel. ADSL modems create multiple channels by dividing the available bandwidth of a telephone line using either frequency-division multiplexing (FDM) or echo cancellation. Both techniques split off a 4-kHz region for basic telephone service at the DC end of the band Synchronous Digital Subscriber Line (SDSL) provides variable, symmetric, high-speed data communication up to 1. 54 Mbps. But SDSL doesn’t allow analog on the same line, as ADSL does. SDSL uses 2B1Q line coding, a technology employed in ISDN and T1 services. SDSL is a viable business option because of its capability to transmit high-speed data over longer distances from the CO and because of its ease of deployment made possible by its spectral compatibility. High Bit-Rate DSL (HDSL) is a symmetric version of DSL that uses 2B1Q like SDSL, but over two-wire pairs. HDSL is targeted at business deployment because it offers full-rate symmetrical 1. 5 Mbps service. HDSL-2 is a standards-based version of HDSL offering symmetrical 1. 5 Mbps service like HDSL, but with a single twisted pair of wires. HDSL is full-rate and does not offer variable rates. G. SHDSL does offer multirate service with symmetrical speeds of up to 2. 3 Mbps. ISDN digital subscriber line (IDSL) is similar in many ways to ISDN. The primary difference is that IDSL is always on and can reach speeds up to 512 kbps with compression. IDSL uses 2B1Q line coding and does not support analog. On the other hand, IDSL does allow data communications over longer distances than other DSL options (up to 26,000 feet) and is considerably less expensive than ISDN service, in most cases. Because IDSL supports existing ISDN CPE, it makes it easy to convert from ISDN to IDSL. Internetworking Technologies Handbook 1-58705-001-3 21-9 Chapter 21 Review Questions Digital Subscriber Line Very-High-Data-Rate Digital Subscriber Line (VDSL) transmits high-speed data over short distances through twisted-pair copper telephone lines. VDSL technology is still in the definition stage, but additional research is required before it can be standardized. VSDL and ADSL are similar technologies. However, although VSDL transmits data at nearly 10 times the rate of ADSL, ADSL is the more complex transmission technology. Review Questions Q – Name the current versions of DSL technology. A – ADSL, SDSL, HDSL, HDSL-2, G. SHDL, IDSL, and VDSL. Q – What are the two-line coding methods used for ADSL? A – DMT and CAP. Q – Which versions of DSL offer symmetrical service? A – SDSL, HDSL, and HDSL-2. Q – What symmetrical version of DSL offers multirate service over a single pair of wire? A – G. SHDSL Q – How far of a reach can IDSL achieve from the CO? A – 26,000 feet. Q – What downstream and upstream rates are proposed for VDSL? A – The maximum downstream rate under consideration is between 51 and 55 Mbps over lines up to 1000 feet (300 m) in length. Downstream speeds as low as 13 Mbps over lengths beyond 4000 feet (1500 m) are also common. Upstream rates in early models will be asymmetric, just like ADSL, at speeds from 1. 6 to 2. 3 Mbps. For More Information ADSL Forum (http://www. adsl. com/) Cisco DSL Depot (http://www. isco. com/warp/public/779/servpro/promotions/dsldepot/) Glossary Terms †¢ G. SHDSL – Asymmetrical Digital Subscriber Line. The upstream data rate is different from the downstream (typically the downstream is greater than the upstream). It is applicable to many DSL technologies offered today; however, this term typically assumes DMT as defined in the ANSI T1. 413 specification. CPE – Customer premises equipment, including devices such as CSU/DSUs, modems, and ISDN terminal adapters, required to provide an electromagnetic termination for wide-area network circuits before connecting to the router or access server. This equipment was historically provided by the telephone company, but it is now typically provided by the customer in North American markets. †¢ Internetworking Technologies Handbook 21-10 1-58705-001-3 Chapter 21 Digital Subscriber Line Glossary Terms †¢ CSU/DSU – Channel service unit/data service unit. Provides electromagnetic termination of the digital (WAN) signal at the customer premises. Performs line conditioning and equalization functions, and responds to loopback commands sent from the central office. In North America, the customer supplies the device providing CSU/DSU functionality; outside North America, the telecommunications service provider usually provides this device. DMT – Discrete Multitone is the ANSI specified modulation technique for G. SHDSL (ANSI-T1. 413). DMT is theoretically capable of more speed than CAP. The key providers of DMT are Alcatel, Amati, Aware/ADI, and Orckit. Downstream – Refers to the transmission of data from the central office (CO or COE) to the customer premise equipment (CPE). HDSL – High-speed Digital Subscriber Line. This is a symmetrical modulation technique that uses two or three pairs of wires. HDSL2 – High-speed Digital Subscriber Line. This is a symmetrical modulation technique that can achieve speeds in the T1 (1. 5 Mbps) range using one copper pair. POTS – Plain old telephone service. QAM – Quadrature amplitude phase modulation. RG. SHDSL – Rate Adaptive Digital Subscriber Line. This refers to the CAP2 and QAM technologies that use variable data rates to maximize the utilization of various loop lengths. SDSL – Symmetric Digital Subscriber Line. This indicates a subscriber line service that utilizes the same data rate for upstream and downstream. This term is applicable to MDSL and HDSL technologies. Upstream – Refers to the transmission of data from the customer premises equipment (CPE) to the central office equipment (CO or COE). VDSL – Very-High-Data-Rate Digital Subscriber Line. This is a high-speed asymmetrical service in the 10 to 25 Mbps range, typically limited to less than 5,000 feet. The targeted application for this technology is a hybrid fiber copper system (fiber to the neighborhood). †¢ †¢ †¢ †¢ †¢ †¢ †¢ †¢ †¢ †¢ Internetworking Technologies Handbook 1-58705-001-3 21-11 Chapter 21 Glossary Terms Digital Subscriber Line Internetworking Technologies Handbook 21-12 1-58705-001-3 How to cite Digital Subscriber Line, Papers

Art Dealer Essay Example For Students

Art Dealer Essay By age five, Michael Irvin loved art and museums but, in retrospect, his was no schoolboy infatuation. Today, his dedication to objets dart has made him one of the most sought-after art dealers in Southern California. The wares of his perenial treasure hunt span his clients estates and summer homes, private planes and yachts anchored in Newport Beach and Monte Carlo. But Irvin is not simply a wholesale art dealer, for this stylish art connoisseur describes his work as part psychologist, part art consultant, and he uses his expertise to interpret and translate his clients artistic expressions. Many of my clients already have everything. Luxury cars, beautiful jewelry, clothes, said Irvin, a rugged 39-year-old who resembles a bronzed and taller Tom Cruise. Their homes are their calling cards, and these homes command exquisite art. These demands require a comprehensive understanding of art history, and celebrities like Dr. Phil McGaw and Orange Countys elites regularly call Irvin. His client roster is a veritable whos who of OC society and includes a top Microsoft executive and a Saudi princess. Unlike traditional art dealers who simply locate art for their customers, Irvin consults with clients who have little time to research and are unsure of their decorative choices. He relies on his extensive database of artists and experts amassed over a decade of work, and buys directly from the source at wholesale prices. Michael has a solid grasp of what his clients want, said Sheldon Harte of Harte Brownlee Associates, a celebrated interior design firm in Laguna Beach. Hes the best in the business. Despite the posh imagery, Irvin, said his daily routine is anything but glamourous. His typical day involves unloading and carrying heavy canvases, wood panels or sculptures in all shapes and sizes. But Irvin doesnt complain. The son of a Dallas fireman, Irvin grew up in Texas and was first exposed to opulance and excess during a stint as a chauffeur for Texas oil tycoons. He later worked as a caterer at the mansions of Stanley Marcus, of Neiman Marcus department stores, and society mavens like Anne Bass. I became acclimated to fine things Id never seen as a kid, said Irvin, who speaks with a slight, charming Southern accent. It was a lifestyle I wanted for myself. Irvin went into business moving fine art to athletes homes in Colorado and Califorina, then settled in Irvine in 2000 and worked at an art gallery in Laguna. When friends constantly asked him for decorating advice, Irvin realized he could parlay his expertise into a specialized business. Irvins company, Studio Art House, was born. The friendships he makes through his work, Irvin said, are his greatest satisfaction. On a recent afternoon, he shared lunch with Larrisa Krupp, a client turned friend, surrounded by the art he chose for her ocean-view Spanish villa in Laguna Beach. I love what I do, he said. I cant imagine anything better than creating beauty and meeting truly intriguing people through my work.