Used For A Single Isdn Line example essay topic

ISDN (Integrated Services Digital Network) is an all-digital communications network designed to bring the power of the digital network directly to the desktop. ISDN, or Integrated Services Digital Network, is a suite of internationally-adopted standards for end-to-end digital communication over the public telephone network. As this network has been traditionally oriented towards voice services, ISDN is an important step forward in the adaptation of the network to handle the increasing global demand for computer-to-computer data communications. ISDN brings us closer to the goal of a ubiquitous multi-service network, integrating voice, data, video and image services in a digital format over a common, global network. ISDN is as easy to use as analog but offers much more. For example, you can utilize the two 64 kbps B channels as individual voice and data lines at the same time.

You can use one channel to talk while you " re using the second to send data files. Or, with ISDN's BONDING capability, you can aggregate both lines into a single high-speed 128 kbps link for dependable transmission that's four times faster than a 28.8 kbps modem. Other benefits include: Voice, data and video can all be sent over a single ISDN line. ISDN connections are made almost instantly - typically less than a second - unlike modems and analog lines which require 30 to 60 seconds before any data can be transmitted. Because it's a digital service, ISDN offers near-perfect line quality that's far superior to analog - so line conditions never force you to fall back to a slower speed THE HISTORY OF ISDN The early phone network consisted of a pure analog system that connected telephone users directly by a mechanical interconnection of wires.

This system was very inefficient, was very prone to breakdown and noise, and did not lend itself easily to long-distance connections. Beginning in the 1960's, the telephone system gradually began converting its internal connections to a packet-based, digital switching system. Today, nearly all voice switching in the U.S. is digital within the telephone network. Still, the final connection from the local central office to the customer equipment was, and still largely is, an analog Plain-Old Telephone Service (POTS) line.

ISDN has been in the making for over a decade and is just beginning to become widely available in the United States. Europe and Japan have enjoyed large-scale deployment of ISDN services for years. North America has just over 70 percent deployment, with availability in most major metropolitan areas. The International Telecommunications Union Telecommunications Standardization Sector (ITU-TSS), formerly known as the International Telephone and Telegraph Consultative Committee (CCITT), is a United Nations organization that coordinates international telecommunications. It was the intention of the ITU-TSS to standardize global telecommunications by implementing ISDN. The idea of standardization is widely accepted but the implementation of ISDN has been slow in coming.

AT&T and Northern Telecom are the two major manufacturers of ISDN switches used by telephone companies. Each manufacturer took different steps to provide the ITU-TSS standards for their equipment, and the end result has been incompatibilities with hardware and software. The incongruities stifled the expansive deployment of ISDN since telephone companies have resisted purchasing products that are incompatible with their existing equipment. National ISDN 1 (NISDN-1) is a United States-specific implementation of ISDN that was adopted by the telecommunications industry in 1991. NISDN-1 was intended to provide conformity to service users regardless of the equipment or software utilized. However, it wasn't until November 1992 that the Transcontinental ISDN Project 1992 (TRIP '92) was held in Reston, Virginia.

TRIP '92 was a trade show with exhibits from vendors, proving that ISDN standardized products and services were available along with applications to support them. Also, the exposition featured the "Golden Splice" event which marked the advent of transcontinental ISDN service. NISDN-1 addresses three areas: 1) standardizing equipment and services, 2) standardizing telephone company procedures for operation, and 3) standardizing communication among central offices. Unfortunately, the NISDN-1 standards are not accepted by all service providers. Southwestern Bell Corp. and U.S. West Inc. do not plan to deploy NISDN-1 services due to incompatibilities with their existing ISDN networks. NETWORK EVOLUTION Sixties - Digital Carrier The telecommunications network began to evolve toward digital transmittion with the introduction of digital carrier facilities between toll / tandem offices and local offices.

This necessitated the use of analog-to-digital (A / D) converters Seventies - Digital Toll Offices During the seventies, telephone companies added digital toll / tandem offices into the network. The reduced the need for back-to-end, analog-to-analog digital (A / D) converts. Early Eighties - Digital Local Offices The digital trend continued into the early eighties with the introduction of digital end or local offices Late Eighties - ISDN Beginning in the late eighties and continuing into the nineties, the introduction of ISDN added end-to-end digital connectivity to the network THE BAS " YC OF ISDN ISDN is based on a number of fundamental building blocks. First, there are two types of ISDN "channels" or communication paths: B-channel The Bearer ("B") channel is a 64 kbps channel which can be used for voice, video, data, or multimedia calls. B-channels can be aggregated together for even higher bandwidth applications.

D-channel The Delta ("D") channel can be either a 16 kbps or 64 kbps channel used primarily for communications (or "signaling") between switching equipment in the ISDN network and the ISDN equipment at your site. These ISDN channels are delivered to the user in one of two pre-defined configurations: Basic Rate Interface (BRI) BRI is the ISDN service most people use to connect to the Internet. An ISDN BRI connection supports two 64 kbps B-channels and one 16 kbps D-channel over a standard phone line. BRI is often called "2 B+D" referring to its two B-channels and one D-channel. The D-channel on a BRI line can even support low-speed (9.6 kbps) X. 25 data, however, this is not a very popular application in the United States. Primary Rate Interface (PRI) ISDN PRI service is used primarily by large organizations with intensive communications needs.

An ISDN PRI connection supports 23 64 kbps B-channels and one 64 kbps D-channel (or 23 B+D) over a high speed DS 1 (or T-1) circuit. The European PRI configuration is slightly different, supporting 30 B+D. BRI is the most common ISDN service for Internet access. A single BRI line can support up to three calls at the same time because it is comprised of three channels (2 B+D). Two voice, fax or data "conversations", and one packet switched data "conversation" can take place at the same time. Multiple channels or even multiple BRI lines can be combined into a single faster connection depending on the ISDN equipment you have. Channels can be combined as needed for a specific application (a large multimedia file transfer, for example), then broken down and reassembled into individual channels for different applications (normal voice or data transmissions).

Integrated Services Digital Network (ISDN) is a fully digital communications technology implemented throughout the infrastructure of the existing worldwide telephone network. ISDN uses a standard phone line (a copper wire pair) in a home or office and converts it from a single analog circuit into multiple high speed digital circuits capable of transmitting audio, still images, motion video, and text data simultaneously. ISDN services make possible videoconferencing and other real time data-intensive applications, and it does so at a price comparable to standard analog service. Standard telephone service requires a separate phone line for each device to be used simultaneously. Not only can multiple lines be expensive, but the amount of information that can be transmitted is limited with analog service; current technology allows 56 kilobits per second (Kbps). ISDN, however, provides multiple channels to operate concurrently on the same pair of wires, and each channel is capable of transmitting at 64 Kbps.

Additionally, digital transmissions allow for reduced noise and interference on the carrier channels. ISDN provides services and capabilities not available through standard telephone service. ISDN furnishes these services through a digital package when a call is initiated. The digital packet includes information regarding: 1) who is calling, 2) the type of call (data / voice /etc... ), and 3) the number dialed, if more than one number is used for a single ISDN line. With the information provided, ISDN equipment can determine how to handle a call, based on user-defined preferences. Calls can be accepted, rejected or even rerouted.

Data calls can even be routed to an Internet Protocol (IP) address. BENEFITS OF ISDN Digital Network From a user's point of view, digital network offers: . increased capacity, . improved noise reduction, and. the ability to transmit both voice and data. Digital Signaling Digital signaling offers: . speed, . access to custom-calling and data-transmittion features, and. potential access to a variety of data-based services. ISDN offers variable, responsive transmission speeds.

Two or more channels can be combined into a single larger transmission "pipe". Channels can be assembled as needed for a specific application (a large video conference, for example), and then broken down and reassembled into different groups for different applications (normal voice or data transmissions). Combining B-channels in this manner is called inverse multiplexing, or "bonding". ISDN is a network architecture that combines all of the advantages of the digital network and digital common-channel signaling and makes them available to the telecommunications user. ISDN BRI service can use data compression which boosts the 128 Kbps transmission rate to between 256 Kbps and 632 Kbps, depending upon the compression ratio used.

It handles all types of information. Unlike some other digital communications technologies, ISDN handles all types of information - voice, data, studio-quality sound, still and moving images. They are all digitized, and transmitted at high speeds in the same flow of data. ISDN handles many devices and many telephone numbers, on the same line. Up to eight separate telephones, fax machines or computers can be linked to a single ISDN connection, and have up to 64 "call appearances" of the same or different telephone numbers.

As many as eight separate devices (telephones, computers, fax machines, and more) can be connected to the same ISDN line and each given as many separate telephone numbers as needed. This means that it is no longer necessary to have multiple telephone lines to handle multiple telephone devices, or multiple telephone numbers, or multiple telephone calls. One ISDN line does it all. It can support up to three calls at the same time.

Two voice, fax or PC "conversations", and one data "conversation" can take place at the same time, through the same ISDN connection. Perhaps the most important single feature of ISDN, is that it offers inexpensive dialed digital access to the worldwide telecommunications network. It is no longer necessary to lease costly dedicated lines for high-speed digital transmission, or to limit data speed and accuracy by using modems to convert digital signals to analog pulses. Digital-to-analog conversions will go away.

Modems to convert the digital signals of PCs, computers, LANs, and other devices to the analog signals needed for an analog network will be replaced. Instead, high-speed pulses will flow directly from one digital device to another through a totally digital network. Many digital connections will become dialed, not dedicated. It will no longer be necessary to lease expensive dedicated digital lines simply to link a high-speed data device to the network. The deciding factor will be the economics of how fast the line must be and how frequently it is used.

LAN protocols such as IP and IPX are better supported by ISDN connections across WANs due to faster connect times (between 1 and 4 seconds) than analog service (between 10 and 40 seconds). ISDN is compatible with other WAN services like X. 25, Frame Relay, Switched Multi-megabit Data Services (SMDS) and higher speed services like Asynchronous Transfer Mode (ATM). THE FUTURE There is and for years has been a global push to become a digital world. The main evidence of the digital age is the internetworking of computers, providing access to a wealth of resources and information. ISDN technology, although plagued by political issues, is a cost-effective means to connect communication equipment of all types. As more of the compatibility issues are resolved, ISDN services will increasingly become the service of choice for businesses and residential customers.

The rise in popularity should drive down equipment costs and make connection devices readily available off-the-shelf. Although other digital services are competitive, most require expensive dedicated lines or possess inherent shortcomings like slow speed. ISDN technology is standardized and provides dynamic high speed end-to-end digital connectivity over the existing worldwide telephone network. ISDN continues to evolve with broadband ISDN availability in the near future.

With ATM-based technology providing B-ISDN transmission speeds up to 600 Mbps or more, one would be hard-pressed to find a viable affordable alternative With ISDN's widespread availability and ease of use, more and more functions will arise benefitting from ISDN services. These up and coming functions are described below. Telemedicine: In the future, the use of ISDN as a video connection will be an economical alternative to patients that has already been diagnosed. Customer Services: Rather than sending programmers and technical staffs to site, software problems can now be solved remotely! ISDN connection will reduce response time and get customers to the right programmers faster. Home / Remote Banking Services: Services like this take very long for staffs to verify and approve banking services.

With the ease of ISDN and computer, a bank's accessibility reach beyond working hours and its regional ity will be expanded when more banks merge together in banking services. Distance Learning: It will allow training, education and institutions from many remote sites. As you can see here, this interactive learning package that you ae using now is in fact one. Imagine Internet loading twice as fast with more graphics / animations and sounds.