Ocb-283

PRACTICAL TRAINING REPORT
AT
B.S.N.L
        [pic]

TRAINING ON: - GENERAL ARCHITECTURE OF OCB-283

CONTENTS

    1. History
    2. Introduction to Electronics Exchange
    3. Basic Principles and Structure of Exchange
    4. Control Stations of OCB-283
    5. Setting up of a Call in Exchange
    6. Main Stages in a Call
    7. Translation and Routing Programs
    8. Translation and Routing Flow Chart
    9. Glossary
    10. Bibliography

                      History
The word telephone, from the Greek roots tele, "far," and phone, "sound," was applied as early as the late 17th   century to the string telephone familiar to children and   was later used to refer to the megaphone and the speaking tube; but in modern usage it refers solely to electrical devices derived from the inventions of Alexander Graham Bell and others. The U.S. patent granted to Bell in March 1876 for the development of a device to transmit speech sounds over electric wires is often said to be the most valuable ever issued. The general concepts involved in the invention of the telephone -- of speech sounds as a complex of vibrations in air that is transferrable to solid bodies and of the convertibility of those vibrations to electrical impulses in conducting metals – had by then been understood for decades. Bell was but one of a number of workers racing to pull them together into a practical instrument for the transmission of speech. Within 20 years of the Bell patent, the telephone instrument, as modified by Thomas Watson, Emil Berliner, Thomas Edison, and others, acquired a form that has not changed fundamentally in a century. Since the invention of the transistor in 1947, metal wiring and other heavy hardware have been replaced by lightweight and compact microcircuitry. Advances in electronics have improved the performance of the basic design, and they also have allowed the introduction of a number of "smart" features such as automatic redialing, call-number...