TELECOMMUNICATION SWITCHING SYSTEMS TC
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INTRODUCTION
The field of telecommunications has evolved from a stage when signs, drum beats and semaphores were used for long distance communication to a stage when electrical, radio and electro-optical signals are being used. Optical signals produced by laser sources and carried by ultra-pure glass fibers are recent additions to the field.
Telecommunication networks carry information signals among entries which are geographically far apart. An entity maybe a computer, a human being, a facsimile machine, a teleprinter, a data terminal, and so on. Billions of such entities the world-over are involved in the process of information transfer which may be in the form of a telephone conversation or a file transfer between two computers or a message transfer between two terminals, etc. In telephone conversation, the one who initiates the call is referred to as the calling subscriber and the one for whom the call is destined is the called subscriber. In other cases of information transfer, the communicating entities are known as source and destination, respectively.
The full potential of telecommunications is realized only when any entity in one part of world can communicate with any other entity in another part of the world.
Modern telecommunication networks attempt to make this idea of ‘universal connectivity’ a reality. Connectivity in telecommunication networks is achieved by the use of switching systems. This subject deals with the telecommunication switching systems and the networks that use them to provide worldwide connectivity.
1.1 Evolution of Telecommunications
Historically, transmission of telegraphic signals over wires was the first technological development in the field of modern telecommunications. Telegraphy was introduced in 1837 in Great Britain and in 1845 in France. In March 1876, Alexander
Graham Bell demonstrated his telephone set and the possibility of telephony, i.e. longdistance voice transmission. Graham Bell’s
www.jwjobs.net
INTRODUCTION
The field of telecommunications has evolved from a stage when signs, drum beats and semaphores were used for long distance communication to a stage when electrical, radio and electro-optical signals are being used. Optical signals produced by laser sources and carried by ultra-pure glass fibers are recent additions to the field.
Telecommunication networks carry information signals among entries which are geographically far apart. An entity maybe a computer, a human being, a facsimile machine, a teleprinter, a data terminal, and so on. Billions of such entities the world-over are involved in the process of information transfer which may be in the form of a telephone conversation or a file transfer between two computers or a message transfer between two terminals, etc. In telephone conversation, the one who initiates the call is referred to as the calling subscriber and the one for whom the call is destined is the called subscriber. In other cases of information transfer, the communicating entities are known as source and destination, respectively.
The full potential of telecommunications is realized only when any entity in one part of world can communicate with any other entity in another part of the world.
Modern telecommunication networks attempt to make this idea of ‘universal connectivity’ a reality. Connectivity in telecommunication networks is achieved by the use of switching systems. This subject deals with the telecommunication switching systems and the networks that use them to provide worldwide connectivity.
1.1 Evolution of Telecommunications
Historically, transmission of telegraphic signals over wires was the first technological development in the field of modern telecommunications. Telegraphy was introduced in 1837 in Great Britain and in 1845 in France. In March 1876, Alexander
Graham Bell demonstrated his telephone set and the possibility of telephony, i.e. longdistance voice transmission. Graham Bell’s