Thestorez.com : Online book store india

Thestorez.com is an Indian online books store with over 100,000 books available for buying online. The bookstore USP is their excellent service. The prices are very low as compared to other online book sites. Once can easily get 25-35% discount on various titles. The list of the books contains all kinds of books from technology books to fiction.

The online book industry is seeing a boom in India. Some major international players are expected to enter soon in this market.

Integrated Drive Electronics (IDE)

SCSI connections may connect both internal devices, which are inside the chassis of your computer and use the computer’s power supply, and external devices. Integrated derive Electronics (IDE) connections, on the other hand, are typically only internal and connect hard disks, CD-ROM derives, and other peripherals inside a PC. A PC motherboard can support two IDE controllers, and each controller in turn can support two devices (a master and a slave).

Small Computer System Interface (SCSI)

The Small Comuter System Interface (SCSI) is built into all current models. You can connect as many as eight devices (ID numbers from 0 to 7) to the SCSI port, but one of them must be the computer itself with ID 7, and one is usually your internal hard disk with ID 0.

Framework for Multimedia Systems

The framework presented here provides an overall picture of the development of distributed multimedia systems from which a system architecture can be developed. The framework highlights the dominant feature of multimedia systems: the integration of multimedia computing and communications, including raditional telecommunications and telephony functions.
Low-cost multimedia technology is evolving to provide richer information processing and communications systems. These systems, though tightly interrelated, have distinct physical facilities, logical models, and functionality. Multimedia information systems extend the processing, storage, and retrieval capabilities of existing information systems by introducing new media data types, including image, audio, and video. These new data types offer perceptually richer and more accessible representations for many kinds of information. Multimedia communication systems extend I existing point-to-point connectivity by permitting synchronised multipoint group communications.

Introduction to Multimedia Technology

A complex weave of communications, electronics, and computer technologies is emerging to create a new multimedia fabric for the next decade. The nature of this cloth is still evolving as an assortment of industries-telecommunications, consumer electronics, computers, cable and broadcast television, and information providers-compete for the emerging market. The potentially biggest near-term market will be the home and consumer, as recent developments such as consumer-oriented computer products, interactive television, and video-on-demand suggest. However, in time many expect the new technologies to be as pervasive as today’s television and telephone and the impact to reach to the sum of computers, telecommunications, and electronics, touching all parts of society from industry to government, education to recreation.
The concepts behind what is emerging today date back to over four decades to a series of visionary thinkers who foresaw the evolution of computers towards richer personalised devices that would become an extension of the individual. In 1945 Vannevar Bush, then the Director of the Office of Scientific Research and Development in the U.S. government, suggested, that one of the future devices available for individuals would be a memex, “a device in which one stores all his books, records, and communications, and which is mechanised so that it can be consulted with exceeding speed and flexibility. It is an enlarged intimate supplement to his memory.” The memex would additionally be an associative device, so that related items could be easily located.
Multimedia Systems
Multimedia technology is breaking down the traditional boundaries between devices for computing, personal communications, and consumer entertainment. Major industries are rethinking their market strategy and forming a web of new alliances connecting entertainment, telecommunications, computing, publishing, and other global enterprises. Multimedia devices are expected to replace ubiquitous appliances such as the telephone and television and change many of the activities associated with them. The large scale of these trends and the many participants in these developments has added to the complexity of the possibilities. This chapter provides a contemporary account of the major technology forces affecting this convergence and identifies the significant near-term issues that lie ahead.

Entertainment

When the average person talks about consumer electronics, TV is what first comes to mind. Television is a very young industry. The first black and white broadcasts started in 1941.Color TV sets were not available at consumer prices until 1964. Cable TV was not widely available in most areas of the united States until the 1980s. Today, the average cable system has more than forty channels to choose from .CNN, MTV, HBO, and the like were not available in the 1960s and only just started in the 1970s,MTS stereo television broadcasts and stereo TV sets have only been available in the 1990s.In Europe and Japan commercial and cable TV has not flourished the way it has in the United States due to regulatory constraints and language barriers. Most countries have fewer than five TV channels.
Consumer electronics in the early 1980s introduced inexpensive home VCRs. The war between Beta and VHS was hot and heavy. Eventually VHS won due to JVC’s aggressive licensing and VHS’s eight-hour capability, The picture quality was poor, and the technology was inferior, but strong marketing won out. Camcorders, another recent innovation, have replaced the 8 mm and super8movie cameras in a very few years. The compact disc (CD) was introduced by philips and Sony in 1981.Today, it’s almost impossible to get a real record (as in LP). Similar changes have occurred in tape recording technology and electronic musical synthesisers.

Communications

In 1980, the Bell System in the United States was still a monopoly. On January 1, 1982, Judge Harold Green dissected the Bell System into Regional Bell Operating Companies (RBOCs), commonly referred to as “Baby Bells”. Bell Labs and Western Electric were also restructured (as American Bell and later renamed AT&T Consumer Products) so as not to have an unfair advantage with the Bell name. With deregulation in place, any number of companies could sell a telephone or provide long-distance service. Years later, most of the cheap $5 phones are a thing of the past. After the FCC opened up the 46-MHz band, use of cordless phones has grown significantly. The FCC has now also opened up a new 900 MHz band for cordless phones, which has extended range and less interference with radio-controlled toys than the 49 MHz band.
In the rest of the world, most countries still have a government monopoly on the phone system, though this is changing because of influence from the U.S. market. The united Kingdom is probably the most progressive non-U.S. market. Cellular phones have been terrified so inexpensively in the united kingdom that most people own cellular phones, Many U.S. companies, such as US West, have set up U.K. subsidiaries to sell cable TV and phone service at 15 percent lower rates than the local monopoly, The monopoly position does have its advantages however, For new technology to take hold in the United States, each of the RBOCs must endorse the new technology and the market must show a need. In other countries, the PTT may proclaim that a certain technology will be adopted (like integrated services Digital network (ISDN) for instance), and there is a government mandate to make it happen. For this reason, Europe is much father ahead in deploying ISDN than the united States.
In the united States, the Federal Communication commission (FCC) has a reasonable scope of influence to open doors for multimedia communications. In 1992, the FCC allocated a new frequency band at 218-219 MHz for interactive video applications. This new band will be used for a nationwide interactive TV service called TV-Answer, which is based on a radio frequency (RF) cellular-like modem. Since most cable networks today are transmit- only. This new RF channel can provide the return communications path for these new services. Home shopping is one obvious use of this technology.

Digital signature

Digital signature is a sequence of bits that are calculated mathematically while signing a given document. Since it is easy to copy, alter or move a file on computers without leaving any trail, one needs to be very careful in designing a signature scheme. In keeping with the properties of a handwritten signature, a digital signature should depend on some secret known only to the signer and on the content of the message should be able to distinguish between a forgery and a valid signature without requiring the signer to reveal any secret information. A general digital scheme consists of three algorithms:
1. A key generation algorithm
2. A signing algorithm
3. A verification algorithm
Cryptography: The process or skill of communicating in or deciphering secret writings or ciphers.
Working of digital signature:
Public key cryptography gives reliable method for digital signing and signature verification system based on public/private key pairs. A person can sign a given digital message with private key. The two steps involved are:
1. Calculate the hash value
In the first step of the process, a hash value of the message is calculated by applying some cryptographic hashing algorithm. The calculated hash value is a sequence of bits, usually with affixed length, extracted in some manner from the message. All reliable algorithms for message digest calculation apply such mathematical that when just a single bit from the input message is changed, a completely different digest is obtained.
2. Calculate the digital signature
In the second step of digitally signing a message, the information obtained in the first step hash-value of the message is encrypted with the private key of the person who signs the message and thus an encrypted hash-value, also called digital signature is obtained.
Verifying signed data
A digital signature is associated with a X.509 certificate which contains the sender’s public key. This key is used to decrypt the digital signature into the original hash value on the recipient’s computer. To verify the digital signature, the same hashing algorithm is used to generate a hash value based on the original data. The decrypted hash value is compared to the generated hash value. If the values match, the digital signature is valid.
1. Calculate the current hash value
2. Calculate the original hash value
3. Compare the current and the original hash-value
Benefits of digital signature:
Authenticity
Although digital signatures alone cannot prevent the content from being manipulated during delivery, using digital signatures provides a mechanism to detect tampering of it occurs. If the data is altered in any way after being digitally signed, the recipient can tell via properties of the signature that the data sent does not match the data received.

Acknowledgement
Data can be signed by the recipient as well as the sender. When a recipient signs the data and returns it to the sender, this signature is an acknowledgement. Digital signatures used in this way also provide no repudiation; the ability to prove that the data was sent by the signer.

Computers

The past ten years have brought much change to the world of computers, communications, and consumer products. Let’s review how far we’ve come. In 1980, personal computers were Apple IIs, Radio Shack TRS80s, Commodore Pets, and perhaps lesser known SOL20s and Exidy Sorcerers. Mini-computers were PDP 11/70 and VAX 11/780. Remarkably, punch cards were still around for those “big jobs.” The Commodore 64 appeared in 1981 and eventually won the home computer war against the likes of game machines such as the Atari 2600 VCS and Atari 5200, Mattel Intellivision, and others because it was a “real” computer instead of just a game machine. The C64 and its successor, the C128, also won over other similar home computers such as the Atari 400/800 and the various flavors of Radio Shack TRS80 models. This was a crazy time for the birth of the home computer. Many companies came and went in an attempt to provide the next hot consumer product.
In 1988, Sharp introduced an electronic organiser call the Wizard. With application programs on solid-state “credit cards”, the Wizard was basically an electronic address book and appointment scheduler. Palmtop computers were introduced in 1990 by Atari with the Portfolio and in 1991 by Hewlett-Packard with the 95LX. There were intended to take the Wizard concept one step further by adding a bigger display, a mini-QWERTY keyboard, and MS-DOS compatibility. Also in 1993 Hewlett-Packard upped the ante with a newer palmtop called 100LX and a subnotebook called the Omnibook 300.
The Newton and CD-I concepts are the first generation of the new convergence of computers, communications, and consumer products. They are not traditional televisions or phones or computers, but a hybrid of each. As new technologies become available, the fine line between these products gets even fuzzier.

WEB PAGE SET UP

Creation of a personal web page
A personal homepage is your means of putting your own information on the world wide web (www). A web page is nothing more than a text file written with special tags that format the contents, point to other pages, andinsert images and sounds. The tags arecalled hypertext markup language, or html.
There are a variety of ways to generate a web page:
• We may create our text file in many different ways using a text editor such as notepad (windows), simpletext(mac) or pico(unix).
• There are many software packages, such as dream weaver, that you can use to generate the html code for you. Additionally most word processing packages such as ms word, will usually save to the HTML format as well.
• We may choose to use a template (an existing frame of a document) and just fill in the details.
We will now discuss some of the basic HTML tags used:
HEAD TAG
tag has no attributes. Several tags are included inside it.
1.BASEFONT Tag
It defines the font size to be used in html document.




2.BASE Tag
It is useful for setting some global parameters of an html document.





3.META Tag
This tag is used to include additional information about the document and can be used to pass additional information to a browser. There is no ending tag for and a document can have multiple tags. The attribute the meta tag are NAME, CONTENT, and HTTP-EQUIV.

CONTENT=”woodworking, cabinetmaking, handmade furniture”>


HTML and colors
There are two ways of defining colors in HTML documents. One involves simple color names , such as blue, cranberry, green, orange etc. However, since different browsers have different lists and since the definitions of individual colors may vary from browser to browser, we recommend using the color numbering scheme. For eg:
000000 means 00or no red, 00 of green, and 00of blue. So, 000000 represents black.# sign is to denote that they represent a color.

BODY TAG
The text and HTML code that goes between the body beginning and ending tags is rendered and displayed in the document area of the browser’s window.

1.TEXT color

The text attribute is used to change the default text color for an entire document.


2. BACKGROUND color

The BGCOLOR attribute is used to set the background of an HTML document to a single color.


3.HYPERLINK colors
Three attributes are used for changing the color of a hyperlink, where the color depends on the current state of the hyperlink. The three possible states are: unvisited, visited , and currently thinking of visiting.
LINK unvisited hyperlink
VLINK visited hyperlink
ALINK a hyperlink the user is thinking of visiting. The A stands for active hyperlink.
LINK=”#FF0000”
VLINK=”#808080”
ALINK=”#FFFF00”>

HTML FONT COLORS
It allows us to change the color of any portion of text.

I am going swimming today

WAP TO SHOW THE WORKING OF STATIC MEMBERS

#include

#include

class test

{private:

int code;

static int count;

public:

void setcode()

{code=++count;}

void showcode()

{cout<<"code--"<

static void showcount()

{cout<<"count--"<

};

int test::count;

void main()

{clrscr();

test t1,t2;

test::showcount();

t1.setcode();

t1.showcode();

test::showcount();

t2.setcode();

t2.showcode();

test::showcount();

getch();

}

Speech Synthesis

A major driving force in speech synthesis has come from text-to-speech (TTS). A TTS system assumes that the text already exists in machine-readable form, such as an ASCII file. The machine-readable form is possible obtained from optical character recognition. TTS converts the text symbols to a parameter stream representing sounds. This includes expanding common abbreviations, such as “Pres.,” and symbols like “&”. Also, the system figures out how to handle numbers: 1492 can be read as a date, and even the dollar amount $1492.00 could be read starting with “fourteen hundred...” or “one thousand four hundred....” After creating a uniform symbol stream. The system creates initial sound parameter representation, often at the world level-some words may simply be looked up in a dictionary.
Other parts of the stream are broken down into morphemes, the syntactic basic units of the language. With luck, a group of text symbols corresponds to one morpheme. It is often the case that there is a regular mapping between the symbols of such a group and some sound, in which case the group can be turned into sound. As a last resort, the system converts individual text symbols to sound using rules. The system synthesises sounds from the parameter string based on an articulatory model or using sampled sounds, LPC, or formats. The synthesis system may store units at the level of phonemes, diphthongs, syllables, or words.

Parametric Representations

Another class of representations has nothing to do with models of hearing or acoustics in particular, but exploits some numerical properties to achieve high-quality audio results. The first major breakthrough in this arena was frequency modulation, developed at Stanford by John Chowning [42,43]. FM had been used for several decades for radio transmission. Chowning discovered that certain combinations of carrier and modulator frequencies could produce waveforms that mimicked the properties of musical waveforms. FM was used in digital synthesisers and other musical devices, mostly by Yamaha. Many PC plug-in cards also use FM chips for sound synthesis.
Other techniques such as granular synthesis, waveshaping, Chant, or the Karplus-Strong algorithm have been investigated in the computer music community and implemented in some synthesisers such as the Korg ½ Series (waveshaping). Techniques in the speech community such as vector quantisation are discussed below.

Sub-band coding

Sub-band coding (SBC) is any form of transform coding that breaks a signal into a number of different frequency bands and encodes each one independently. This decomposition is often the first step in data compression for audio and video signals.
The utility of SBC is perhaps best illustrated with a specific example. When used for audio compression, SBC exploits what might be considered a deficiency of the human auditory system. Human ears are normally sensitive to a wide range of frequencies, but when a sufficiently loud signal is present at one frequency, the ear will not hear weaker signals at nearby frequencies. We say that the louder signal masks the softer ones. The louder signal is called the masker, and the point at which masking occurs is known, appropriately enough, as the masking threshold.The basic idea of SBC is to enable a data reduction by discarding information about frequencies which are masked. The result necessarily differs from the original signal, but if the discarded information is chosen carefully, the difference will not be noticeable.
The simplest way to encode audio signals is pulse-code modulation (PCM), which is used on audio CDs, DAT recordings, and so on. All digitization represents continuous signals with a finite set of numbers, and is thus fundamentally inexact. The more bits (numbers) used, the finer the granularity in the digital representation, and the smaller the error. Such quantization errors may be thought of as a type of noise, because they are effectively the difference between the original source and its binary representation. With PCM, the only way to mitigate the audible effects of these errors is to use enough bits to ensure that the noise is low enough to be masked either by the signal itself or by other sources of noise. A high quality signal is possible, but at the cost of a high bitrate (over 700 kbit/s for one channel of CD audio, e.g.). In effect, many bits are wasted in encoding masked portions of the signal because PCM makes no assumptions about how the human ear hears.More clever ways of digitizing an audio signal can reduce that waste by exploiting known characteristics of the auditory system. A classic method is nonlinear PCM, such as mu-law encoding (named after a perceptual curve in auditory perception research). Small signals are digitized with finer granularity than are large ones; the effect is to add noise that is proportional to the signal strength. Sun's Au file format for sound is a popular example of mu-law encoding. Using 8-bit mu-law encoding would cut the per-channel bitrate of CD audio down to about 350 kbit/s, or about half the standard rate. Because this simple method only minimally exploits masking effects, it produces results that are often audibly poorer than the original.

Methods of Encoding the Analog Signal

Real-world requirements may make it impossible to handle the full bit stream of, for example, CD-quality audio. One solution (delta modulation is to encode not the value of each sample, but the difference between one sample and the next. In most cases, fewer bits per sample need to be transmitted, but delta modulation has problems. A more practical variant is called adaptive delta pulse code modulation, or ADPCM. In order to handle both signals that change quickly as well as signals that change slowly, the step size encoded between adjacent samples varies according to the signal itself. In other words, if the waveform is changing rapidly, large steps can be quantised. This is the method used in CD-I (compact disc-interactive), discussed below.
For speech signals, a widely used system works with a quantisation step size that increases logarithmically with the level of the signal. This means that the quantisation levels are closest together when the signal is quiet and spaced further apart when the signal is louder. CCITT Recommendation G.711 codifies the A-law and u-law encoding scheme whereby speech is transmitted at 8 kHz.

Digital Representations of Sound

Time-Domain Sampled Representation
Sound in the analog world is said to be continuous in both time and amplitude. The sound’s analog amplitude can be measured to an arbitrary degree of accuracy, and measurements can be taken at any point in time. A digital signal is different; the signal is defined only at certain points in time, and the signal may take on only a finite number of values.
To sample a signal means to examine it at some point in time. Sampling usually happens
at equally separated intervals, at a rate called the sample frequency, determined by the
Sampling Theorem. If a signal contains frequency components up to some frequency f, then
the sample frequency must be at lease 2f in order to reconstruct the signal properly. In
practical systems, the sample frequency must be higher than 2f. In the early days of digital
audio, sample frequencies at 44.1 kHz and 48 kHz were adopted to handle the full 20-kHz
range of human hearing. The sample frequency of 32 kHz is also common. In multimedia
systems for the PC market, submultiples of 44.1 (22.05 kHz, 11.025 kHz) are often found.
The highest frequency that can be handled (i.e., one-half the sample rate) is often called the Nyquist frequency.
To quantise a signal means to determine the signal’s value to some arbitrary degree of accuracy. The digital signal is defined only at the times where the vertical bars occur. The height of each vertical bar can take on only certain values, shown by dashed lines, which are sometimes higher and sometimes lower than the original signal. If the height of each bar is translated into a digital number, then the signal is said to be represented by pulse-code modulation, or PCM. Pohlmann gives a good overview of other digital representations of sampled signals. (In the world of digital music, a sampled and quantised signal shown by the vertical bars in figure 1.9 (a) is called simply a sampled signal, to distinguish it from signals synthesised, for example, with frequency modulation; this is discussed below in more detail.)

Animation

What is animation? To put it simply, animation is the illusion of movement. When you watch television, you see lots of things moving around. You are really being tricked into believing that you are seeing movement. In the case of television, the illusion of movement is created by displaying a rapid succession of images with slight changes in the content. The human eye perceives these changes as movement because of its low visual acuity. The human eye can be tricked into perceiving movement with as low as 12 frames of movement per second. It should come as no surprise that frames per second (fps) is the standard unit of measure for animation. It should also be no surprise that computers use the same animation technique as television sets to trick us into seeing movement.

Morphing

Morphing is a special effect in motion pictures and animations that changes (or morphs) one image into another through a seamless transition. Most often it is used to depict one person turning into another through some magical or technological means or as part of a fantasy or surreal sequence. Traditionally such a depiction would be achieved through cross-fading techniques on film. Since the early 1990s, this has been replaced by computer software to create more realistic transitions.In early feature films a morph would be achieved by cross-fading from the motion picture of one actor or object to another. Because of the limitations of this technique the actors or objects would have to stay virtually motionless in front of a background that did not change or move in the frame between the before and after shots.Later more sophisticated cross-fading techniques were employed that faded different parts of one image to the other gradually instead of fading the entire image at onceThe effect is technically called a "spatially-warped cross-dissolve".
Morphing software continues to advance today and many programs can automatically morph images that correspond closely enough with relatively little instruction from the user. This has led to the use of morphing techniques to create convincing slow-motion effects where none existed in the original film or video footage by morphing between each individual frame (see optical flow). Morphing has also appeared as a transition technique between one scene and another in television shows, even if the contents of the two images are entirely unrelated. The software in this case attempts to find corresponding points between the images and distort one into the other as they crossfade. In effect morphing has replaced the use of crossfading as a transition in some television shows, though crossfading was originally used to produce morphing effects. Morphing is used far more heavily today than ever before. In years past, effects were obvious, which led to their overuse. Now, morphing effects are most often designed to be invisible.

Vector graphics

.Vector graphics (also called geometric modeling or object-oriented graphics) is the use of geometrical primitives such as points, lines, curves, and polygons, which are all based upon mathematical equations to represent images in computer graphics. It is used in contrast to the term raster graphics, which is the representation of images as a collection of pixels, and used as the sole graphic type for actual photographic images.
Most computer displays translate vector representations of an image to a raster format. The drawing software is used for creating and editing vector graphics. You can change the image by editing these objects. You can stretch them, twist them, colour them and so on with a series of tools. The raster image containing a value for every pixel on the screen, is stored in memory. Starting in the earliest days of computing in the 1950s and into the 1980s, a different type of display, the vector graphics system, was used. In these "calligraphic" systems the electron beam of the CRT display monitor was steered directly to trace out the shapes required, line segment by line segment, with the rest of the screen remaining black. This process was repeated many times a second ("stroke refresh") to achieve a flicker-free or near flicker-free picture. These systems allowed very high-resolution line art and moving images to be displayed without the (for that time) unthinkably huge amounts of memory that an equivalent-resolution raster system would have needed, and allowed entire subpictures to be moved, rotated, blinked, etc. by modifying only a few words of the graphic data "display file." These vector-based monitors were also known as X-Y displays.A special type of vector display is known as the storage tube, which has a video tube that operates very similar to an Etch A Sketch. As the electron beam moves across the screen, an array of small low-power electron flood guns keep the path of the beam continuously illuminated. This allows the video display itself to act as a memory storage for the computer. The detail and resolution of the image can be very high, and the vector computer could slowly paint out paragraphs of text and complex images over a period of a few minutes, while the storage display kept the previously written parts continuously visible. The image retention of a storage display can last for many hours with the vector storage display powered, but the screen can clear instantly with the push of a button or a signal from the driving vector computer.
Vectorising is good for removing unnecessary detail from a photograph. This is especially useful for information graphics or line art. (Images were converted to JPEG for display on this page.)
The term vector graphics is mainly used today in the context of two-dimensional computer graphics. It is one of several modes an artist can use to create an image on a raster display. Other modes include text, multimedia and 3D rendering. Virtually all modern 3D rendering is done using extensions of 2D vector graphics techniques. Plotters used in technical drawing still draw vectors directly to paper.

ATM & ADSL

A Virtual Channel (VC) denotes the transport of ATM cells which have the same unique identifier, called the Virtual Channel Identifier (VCI). This identifier is encoded in the cell header. A virtual channel represents the basic means of communication between two end-points, and is analogous to an X.25 virtual circuit.
A Virtual Path (VP) denotes the transport of ATM cells belonging to virtual channels which share a common identifier, called the Virtual Path Identifier (VPI), which is also encoded in the cell header. A virtual path, in other words, is a grouping of virtual channels which connect the same end-points. This two layer approach results in improved network performance. Once a virtual path is set up, the addition/removal of virtual channels is straightforward.
ATM has proved very successful in the WAN scenario and numerous telecommunication providers have implemented ATM in their wide-area network cores. Also many ADSL implementations use ATM. However, ATM has failed to gain wide use as a LAN technology, and its complexity has held back its full deployment as the single integrating network technology in the way that its inventors originally intended.
Many people, particularly in the Internet protocol-design community, considered this vision to be mistaken. Their argument went something like this: We know that there will always be both brand-new and obsolescent link-layer technologies, particularly in the LAN area, and it is fair to assume that not all of them will fit neatly into the synchronous optical networking model for which ATM was designed. Therefore, some sort of protocol is needed to provide a unifying layer over both ATM and non-ATM link layers, and ATM itself cannot fill that role. Conveniently, we have this protocol called "IP" which already does that. Ergo, there is no point in implementing ATM at the network layer.
In addition, the need for cells to reduce jitter has reduced as transport speeds increased (see below), and improvements in Voice over IP (VoIP) have made the integration of speech and data possible at the IP layer, again removing the incentive for ubiquitous deployment of ATM. Most

Assymetrical Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call. A splitter or micro filters allow a single telephone connection to be used for both ADSL service and voice calls at the same time. Because phone lines vary in quality and were not originally engineered with ADSL in mind, it can generally only be used over short distances, typically less than 3mi (5 km). At the telephone exchange the line generally terminates at a DSLAM where another frequency splitter separates the voice band signal for the conventional phone network. Data carried by the ADSL is typically routed over the telephone company's data network and eventually reaches a conventional internet network.
The distinguishing characteristic of ADSL over other forms of DSL is that the volume of data flow is greater in one direction than the other, i.e. it is asymmetric. Providers usually market ADSL as a service for consumers to connect to the Internet in a relatively passive mode: able to use the higher speed direction for the "download" from the Internet but not needing to run servers that would require high speed in the other direction.