Batería de calor

In this chapter we have seen the tremendous opportunities and benefits that exist for those who invest in CT technology. This applies both to customers and to those in the CT value chain who provide the individual components that make up working CT systems.

This chapter has demonstrated the importance of interoperability and modularity in the design of CT components. The people described in each scenario were able to build and use their CT solutions because they were able to go to different sources for the pieces that make up the final solution. No single vendor could have provided the complete solution. Each involved the customer integrating multiple components and customizing the solution to meet specific needs.

These scenarios have become possible as a result of the maturation of CT technology and the associated recognition of the CT value chain. Given how very compelling these scenarios are, market forces (the economics of interoperability) will encourage vendors to build CT Plug and Play products so that solutions like the ones described can be realized with even greater ease. The steps in building or customizing a complete CT solution from individual components, or for building an individual component that is to be used as part of a CT solution, include the following:

1. Familiarize yourself with all of the technology, functionality, and value that is added at each layer.

2. Decide which layers you can or want to do yourself, and which ones you'd be better off relying on someone else to provide.

3. Decide what functionality you need to provide in your CT component, or at each layer in your CT system.

4. Armed with the resulting knowledge, proceed with the implementation of your system or component.

Regardless of where you fit into the value chain, it's a good idea to be aware of what takes place above and below. Then, and only then, can you be sure that you are taking full

advantage of the opportunity that CT represents to you or your organization. This book provides a thorough insight into the technologies and considerations associated with each layer. As shown in Table 2-1, we will be working our way through the value chain from the bottom up. (This book is designed, however, so that you can go directly to the chapter

corresponding to the layer you are most interested in if you wish. References will guide you back to key concepts you might have skipped.)

Table 2-1. CT value chain

Layer Role See Chapter

Telephone Network Providers

Provide telephone network access and services

3, 4, 5, 8, 10 Telephone Equipment

Vendors

Provide equipment for connecting to telephone network

3, 4, 5, 10

Implement CTI interfaces 6

Implement media services interfaces 7 Implement new switching fabric

technologies

8 Implement administrative services 9 Computer Hardware

Vendors

Provide hardware platforms for CT software 11 Operating System Vendors Provide software platform for CT software 12 Telephony Software

Vendors

Provide indispensable CT-specific software 12 Mainstream Application

Vendors

Provide mainstream/mission-critical application software

12 CT System Integrators Assemble and integrate components for CT

solutions

10, 11, 12, 13 CT System Customer Build and/or customize CT solutions 13

Individuals Use and customize CT solutions 13

Callers Benefit from CT solutions

Chapter 3

Telephony Concepts

More than a century of innovation and creative product development have created an

extraordinarily diverse range of telephony products and technologies. This diversity, like the diversity seen in computer technology, has benefited customers with a wide array of

technology choices. But unlike the computer industry, which always has been reined-in by the need for highly functional interoperability and standardization of component interfaces, the telephony industry traditionally has not had to address the need for integrating with the

products of other vendors. (Their traditional worry has been interoperability among telephone networks.) As a result, vendors have developed their own unique feature names, terminology, and user frameworks.

Despite the tremendous diversity in how telephony equipment vendors actually implement the products and interfaces that allow telephone calls to be placed, the basic concepts are, in fact, universal.

The functional diversity, lack of consistency, rapid innovation, and competitiveness found in the telephony industry have been both a blessing and curse for those challenged with making CT technology ubiquitous.

In recent years various industry organizations such as the ITU, ECMA, Versit, and ECTF have undertaken to build a common framework with standardized terminology so that any

telephony product or feature can be described universally. This framework and related

interoperability specifications not only provide a consistent overall architecture for everyone working with computer telephony technology, but also supports the rich diversity of features and capabilities found in proprietary approaches. A fundamental aspect of these efforts has been in developing a consistent body of nomenclature to replace the arbitrary and proprietary terminology that obscures the many fundamental similarities between implementations. In this way developers, users, and everyone else in the CT value chain can base their plans, designs, and implementations on a common framework.

This book explains telephony technology using this vendor-independent framework. With these concepts, you'll be able to interpret and compare the telephony features of any set of products.

This chapter presents the universal telephony concepts by explaining the various types of telephony resources that can be found in a telephone system and the entities they manipulate. These concepts can be applied to any telephony product by modeling the mechanical,

electronic, and software components3-1 _{that make up its implementation as a telephony}

resource set. (Telephony products are discussed and modeled in Chapter 10.)

3-1 _{Human system components — To be complete, it should be noted that some telephone systems}

(especially antique ones) include humans to implement one or more of the telephony resources in addition to mechanical, electrical, and software components. This is referred to as "putting humans in the system." In most cases humans are considered users of the system and are therefore outside it.