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Integrated services digital network (ISDN).

Integrated Services Digital Network (ISDN)


The business environment that corporations find themselves in today is characterized as being technologically volatile and increasingly competitive. As a result of these environmental conditions, prerequisites to successful business management have changed. Business must now develop decision-making, organizational, and support structures that allow them to adapt quickly to the ever-changing landscape. They need to be able to analyze the impact of external forces, focus and refocus strategies and policies, communicate changes rapidly to managers, and quickly implement these changes on national, regional, and local levels. To accomplish this, they need total command of all information available to each and every part of their organization.

To achieve this ambitious goal, corporations must put an information structure in place that supports the strategy and objectives of the corporation. Integrated Services Digital Network (ISDN) is a technology that can be used to build a structure supporting a comprehensive, integrated, corporate network.

In order to appreciate the benefits of ISDN, it is important to understand the trends affecting information movement and management needs. The main trend is the increased use of information as a strategic asset. By this, we mean the use of information services to gain a competitive advantage through such means as improved decision making and increased productivity.

Another trend is the increased use of "intelligent tools" for office workers, such as personal computers, file servers, print servers, and personal computer networks. As these tools come into wider use, we are seeing an increased emphasis on corporate and inter-corporate information movement. Communication links between corporations end-users, their suppliers, and their customers are becoming vital elements in gaining a competitive edge.

Dedicated Communications Systems

In order to meet this need for improved information movement and management, many corporations are turning to dedicated communications systems. By dedicated systems, we mean private corporate networks using multiplexers and local and wide area networks to improve overall connectivity for the end-user. These private networks have also led to an increase in the use of digital facilities on the public network. These trends can be translated into eight basic corporate information movement and management needs:

* Cost control

* Investment protection

* Connectivity

* Flexibility

* Performance

* Integration

* Globalization

* Manageability.

Let's address these eight needs in more detail.

Business needs to control costs and protect their investment. Their investment in communications products and services must have a positive impact on their business revenues today and keep pace with growth and changing system requirements in the future. They also need to enhance the connectivity and flexibility of their systems. They need systems that interact easily and in a way that is transparent to the user. These systems must also be easily modifiable to meet day-to-day operational requirements.

The strategic value of information has created a need for enhanced performance. Businesses need quality systems with ever-improving standards of reliability. They also need to globalize their networks. They need access to prompt, reliable international communication.

Integration is critical as well. Businesses need systems that can share resources, such as network management tools and processors, instead of requiring stand-alone equipment. And finally, they require better manageability. They need monitoring and control capability for the communications networks in all three network operating environments: premises, local exchange, and inter-exchange.

Investment protection. Cost control. Connectivity. Flexibility. Performance. Globalization. Integration. Manageability. This is an information systems department's shopping list. It is not an easy one to fill. But ISDN provides a path to information movement and management tools that will impact every one of these needs.

Integrated services digital network -- what is ISDN? The CCITT defines ISDN as a network evolved from the telephony integrated digital network (IDN) that provides end-to-end digital connectivity to support a wide variety of services to which users have access through a limited set of standard multipurpose customer interfaces.

The basic concept of ISDN is to provide business with integrated access to an array of services in a global network. This network will be capable of transmitting voice, data, video, and text in a digital format. The key to realizing such a network is the establishment of a standard set of interfaces that allow intelligent devices on corporate premises to talk across a digital link to other intelligent devices located throughout an intelligent network.

AT&T views ISDN as an enabling technology: a basic building block using international standards that will allow the development of these intelligent, integrated, global information systems. Why is ISDN important? Because networking is the key to a corporation's growing need to manage information as a strategic asset. It helps them integrate their information movement and management by linking various applications, utilizing different technologies, and spanning vast distances.

Image of Enabling Technology

Understanding why ISDN is so important requires some technical background. Let's begin by creating a mental image for discussing this enabling technology. Picture a five-pointed star with ISDN at its center. Each of the star's five points represents a principle guiding the development of all AT&T products and services, including ISDN. These principles are:

* Openness to standards

* Modularity

* Communications-based intelligence

* Network management and control

* Integrated products and services.

We'll work our way around the ISDN star beginning with openness to standards. Openness refers to the public standards for ISDN formulated by the CCITT committee. CCITT has defined two ISDN interfaces for use in connecting devices to an ISDN network. Each of these interfaces is composed of "B" channels and "D" channels. Each "B" channel carries user information. It provides a 64 kilobit per second (KBPS) path for information transport.

The "D" channel is an out-of-band channel used for transmitting signaling data needed to properly route the information being carried over the "B" channels. This is a key to intelligent networking because instructions for transmission travel in this channel and tell premises computers, voice terminals, telephone systems (PBXS), and other devices what to do with their information. This makes for a more efficient, cleaner, and secure network.

The first of the interfaces defined by CCITT is called basic rate interface (BRI). This interface provides a standard access between the end-user workstation and the switch, such as a PBX or a central office switch (the phone system used by the local operating company). Basic rate consists of two 64KBPS "B" channels and one 16KBPS "D" channel.

The second interface defined by the CCITT is primary rate (PRI). Primary rate standardizes high speed access between a PBX and the switched network, between two PBXs, or between a PBX and a host computer. This interface consists of 23 64KBPS "B" channels and one 64KBPS "D" channel. With both interfaces, the "B" channels are used for any combination of voice, data and image transmissions. The "D" channel carriers call control and signaling information.

These ISDN interfaces perform the functions of the lower three layers of the open systems interconnection model defined by the international standards organization. Work is underway to develop upper layer ISDN protocols which will facilitate ISDN applications development.

Openness to these standards is an essential part of any commitment to serve corporate networking needs. It is the best way to support the products and services of the many different vendors which make up the typical network. And it is an essential part of protecting the investment a business has already made in their network.

The issue of investment protection brings us to the second point on our ISDN star: modularity. Companies have indicated to us that being able to upgrade their communications systems without having to start over from scratch is very important to them. Modularity in ISDN components is essential to delivering flexible and upgradeable system designs. To be effective, modularity must apply throughout the corporate network -- from the AT&T network service node all the way to the desktop workstations.

The components of any corporate network fall into three information movement and management operating environments. They are the premises systems, the local exchange network, and the interexchange network. Until recently, the business world expected basic connectivity in the local exchange and interexchange environments but less interoperability between systems on their own premises. Now they require connectivity between all three environments.

Let's start by looking at the interexchange environment. Today, AT&T provides primary rate interface (PRI) capability in this environment. The early trial users of network PRI have accessed it through a switch (PBX) on their own premises.

Implementation of AT&T's primary rate interface in our service nodes will provide a direct, intelligent interface between our customer's premises and various AT&T nodal services. This interface will allow communication between intelligent switching systems in our network and at our customer's facilities. In the local exchange environment, AT&T network systems division has introduced ISDN features in the 5ESSTM central office switching machine and other products -- and finally, the end-user domain. This domain consists of end-user workstations, data processing systems, and premises switching systems (i.e., PBX-LANs) such as the AT&T System 85 PBX.

The components offered in the three information movement and management environments will form a flexible, end-to-end ISDN family of products and services capable of handling any number of networking needs. The modularity built into each area insures that a business will be able to upgrade their networks without having to start over. As their needs change and ISDN applications evolve, they will be able to adapt their system accordingly.

Now let's move on to the third point on our ISDN star -- the concept of communications-based intelligence. Basically, this attribute provides networking options that users control. It allows them to take advantage of networking intelligence wherever it resides, whether on the premises, in the networks connecting the premises, or both.

ISDN is a perfect example of communications-based intelligence. The primary rate interface link between the premises and the public portion of the network gives the ability to determine the configuration of a network on a call-by-call basis.

The fourth point on the ISDN star is network management and control. AT&T's goal in this area is to provide to the corporate network management center a common interface -- whether it's a simple terminal or a complex control center -- that allows them to manage and control all their network services and systems. Through the additional information available on the signaling channel, ISDN will play an important role in this network management concept.

The fifth and final point on the ISDN star is integrated products and services. When we discussed modularity, we looked at the components necessary to create an end-to-end ISDN solution. But the technology provided by these components is not enough to meet the needs of most corporations. We need to enhance their applications as well. ISDN has enabled us to do just that.

Applications Development

AT&T has focused on three initial areas for ISDN applications development. These areas are voice networking, data networking, and telemarketing. In public voice networking, the major advantage of ISDN is call-by-call service selection. What this means is giving the information systems manager the ability to allocate specific nodal services based on information passed on the out-of-band, or "D," channel from the PBX to the AT&T ISDN service node.

For example, in the public network, primary rate interface provides shared access for a number of services directly into the service node through a T1.5 access link. The link provides "D" channel signaling for up to 23 "B" channels on that PRI and can be used to do the signaling for 19 additional 24 channel PRI links. This out-of-band signaling is used for selecting the appropriate service on the network for each transmission over the "B" channels. At the premises end, the ISDN interface allows the PBX to allocate its network resources in an evenly distributed manner, creating a more efficient and flexible network of services. Providing these intelligent communications links between the network-based services and the premises-based products enhances the overall performance of the corporate network.

Our second area of applications development is data networking. The dynamic allocation of network access which ISDN brings to voice networking also benefits the data user. Using an ISDN interface, channels can be allocated on a call-by-call basis. This allows access for high speed transfer of data, and the end-user can do so without having to install dedicated facilities.

ISDN technology significantly improves the transmission speeds and connectivity of an existing workstation. For example, a typical configuration today uses a 1,200 bit per second modem to transfer information from a user's workstation to the PBX and from the PBX to a host or another workstation. A ten kilobit file transferred at 1,200 bits per second takes 11 seconds. Using one of the ISDN interfaces 64 kilobit per second "B" channels, that same file can be transferred in one and a half seconds.

Our third area of ISDN applications development is telemarketing. ISDN brings a number of valuable enhancements to telemarketing centers. For example, through the use of the automatic number identification feature on the "D" channel, which passes the callers telephone number out to the person they are calling, the host computer -- through the PBX -- will be able to identify the caller before the telemarketing agent answers the call.

Using the technology of the PBX combined with the features in the database application system, it's possible to send the caller's records to a database for automatic retrieval. Key customer information can be displayed for the agent before they speak to the caller. This saves time in processing the call and enhances the telemarketing company's image in the eyes of its clients.

Automatic number identification also creates the ability to identify callers by geographic area without using different 800 numbers to distinguish callers' locations. It will also provide identification down to the exchange and/or line number. This kind of detailed information can help telemarketers to pin-point analysis of their advertising and sales efforts.

In the future, ISDN will also help when a telemarketing center receives more calls than it can handle. Using the automatic number identification feature, ISDN could enable a telemarketing application to record a caller's number and play a tape saying the company will call back when an agent is available.

And finally, customized call handling could be used by telemarketers. For example, hotel reservation centers could keep a database of preferred customers. This information would come up when these customers call, providing reservation clerks with key information and allowing them to answer the call according to a customized company policy. All these technological advances combine to boost the productivity and lower call handling charges of telemarketing centers while keeping customers happy.

More on the Horizon

AT&T sees voice networking, data networking, and telemarketing as three areas where ISDN enhancements are immediately viable. But companies should be aware that there's much more on the horizon. For example, ISDN technology will make teleconferencing easier by using on-demand switched digital services. For example, video teleconferencing will no longer require a dedicated link that may or may not be in service all the time. Teleconferencing will become a much more viable and cost-effective option for day-to-day operations.

Crisis management or disaster recovery is another application enhanced by ISDN through the use of on demand switched digital services. And finally, ISDN will provide immeasurable help in the field of electronic order entry. As the network continues to evolve and more data become available through signaling channels, electric order entry operations will be able to reap all the benefits of user to user information capability, station identification information, automatic number identification, and on-demand switched digital services.

These applications are only the beginning. Over the years, AT&T has found that our customers are always uncovering innovative ways to use our products and services. As we listen to our customers and combine their ideas with the enabling technology of ISDN, many more applications surface. To recap, the basic consept of ISDN is to provide corporations with integrated access to an array of services in a global network. This network will be capable of transmitting voice, data, video, and text in a digital form.

The key to realiing such a network is the establishment of an international set of interfaces that allows intelligent devices on the premises to talk across a digital link to other intelligent devices located throughout a corporate network. AT&T views ISDN as an enabling technology -- a basic building block using international standards that will allow the development of enhanced information systems.

We have just covered AT&T's approach to developing ISDN technology. We did so by creating a mental picture of a five-pointed star with ISDN at its center. Each of the five points of the star represented a principle guiding AT&T's implementation of ISDN. These principles are openness to standards, modularity, communications-based intelligence, network management and control, and integrated products and services.

Test Sights

But our confidence in ISDN is not solely based on the potential benefits. As part of our commitment to the development and implementation of ISDN products, services, and applications, we have identified several ISDN test sites within the corporation. Let's look at one of those sites.

American Transtech is a division of AT&T formed at divestiture to handle the massive volumes of stock transactions needed to meet the requirements of the divestiture ruling. Since then, Transtech has entered into the telemarketing business, establishing the fourth largest telemarketing center in the country and processing over a million transactions a day.

The two main features of ISDN in use at Transtech are call-by-call service selection and automatic number identification, or info-2. In the present environment, most of the daytime activities are related to inbound programs. Outbound telemarketing activities are handled primarily in the evening.

With call-by-call service selection, most of the [Megacom.sup.R] trunks associated with the outbound programs would be converted to call-by-call trunks and used to supplement a reduced number of [Megacom.sup.R] 800 trunks for inbound programs during the day.

A dealer locater application uses the automatic number identification feature. Previously, customers calling in on the 800 number to get the nearest dealer for a particular product or service were greeted by an agent. The agent asked for the caller's phone number or zip code, entered it via a terminal and brought up a screen of dealer information.

In the ISDN environment, the caller's phone number automatically is passed to the record's database. The screen containing dealer information will be brought up at the same time that the call is delivered to the agent. This reduces the amount of time the caller has to hold while the agent calls up the data. It also increases agent productivity, allowing them to handle more requests more efficiently.

Call-by-call service selection and info-2 require the interaction of a number of hardware and software systems. Let's look at the benefits derived from this ISDN solution. The first benefit is the access efficiencies gained through the use of call-by-call services. Estimates are that we've improved the efficiency of the line usage at American Transtech through the use of call-by-call service selection.

As we noted, the productivity and efficiency of our agents is also enhanced. With the dealer locater service, the cost of handling calls can drop dramatically, because the answering agent has to do far less information gathering to answer the caller's questions. Transtech officials estimate they've cut call handling time significantly, attributing much of the improvement to info-2 on [Megacom.sup.R] 800 service. Just imagine the impact this could have on a call intensive telemarketing business, such as catalog ordering houses.

Transtech will also be able to utilize high speed data transfer on demand through switched digital services carried over a primary rate interface bridge between the 4ESS (AT&T network node) and the AT&T system 85 PBX. In addition, enhanced management reporting software modifications were made to Transtech's AT&T call management system. These modifications provide monitoring of the main traffic bearing channels through the "D" channel information on the primary rate interface.

Our experience with out network and our test site has clearly demonstrated that ISDN is a powerful technology that influences virtually every aspect of an information movement and management system. As we have shown, it will enhance connectivity, flexibility, performance, cost control, investment protection, globilization, integration and manageability. Clearly, ISDN directly addresses the most pressing information movement and management needs. And AT&T is committed to delivering these many benefits to our customers.


Let's summarize what our five basic qprinciples represent in terms of the benefits we've been discussing.

* Openness, as we've noted, will improve our end-user systems connectivity and help support the globalization of their network.

* Modularity protects their current and future networking investments through all levels of ISDN components.

* Using ISDN, communications-based intelligence increases the performance and flexibility of corporate networking systems.

* Network management and control through ISDN will enhance the integration and manageability of the information moving on these networks.

* AT&T's commitment to integrated ISDN products and services provides an end-to-end networking, hardware, and applications solution.

Today, even as standards are evolving, ISDN is a real and vital piece of the strategic information movement and management puzzle. AT&T is in the forefront of those dedicated to bringing ISDN benefits to the marketplace.

Frank P. Young is Division Manager, ISDN Applications Planning at AT&T.
COPYRIGHT 1989 St. John's University, College of Business Administration
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

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Author:Young, Frank P.
Publication:Review of Business
Date:Sep 22, 1989
Previous Article:The telephone as computer.
Next Article:Potential barriers to the implementation of computer-aided direct marketing systems.

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