Презентация на тему: " Lecture#03 Plain Old Telephone Service (part I) The Bonch-Bruevich Saint-Petersburg State University of Telecommunications Series of lectures Telecommunication." — Транскрипт:
Lecture#03 Plain Old Telephone Service (part I) The Bonch-Bruevich Saint-Petersburg State University of Telecommunications Series of lectures Telecommunication networks Instructor: Prof. Nikolay Sokolov,
Forecast (XV century) The time will come when people from the most distant countries will speak to one another and answer one another. Leonardo da Vinci
History of microphones liquid-based microphone carbon microphone modern microphone
Dialing equipment One of the most important elements of a telephone set is dialer. On the initial stage of the telephone communications development there was no dialer. Automatisation of the telephone communications created the demand for such an element as part of the terminal equipment. First dialers were mechanical. They are known as disc dialers. Then the key pulsers emerged. Both type of the dialers send into the subscribers line signals with standardized parameters of pulse durations and pauses between pulses. After that a new type of dialers was invented, which send multifrequency signals, known by acronym DTMF. Two types of the telephone dialer
Telephone communications system "Telephone communications system" term is usually refers to base principles of telephone networks construction, operation and development. These principles usually include the following positions: purpose of the system; supported services; network structure; quality of service ratings; numbering plan; maintenance; equipment requirements; main directions of system development.
Main abbreviations PSTN – public switched telephone network, UTN – urban telephone network, RTN – rural telephone network, ISC – international switching centre, (U/T)LDE – (universal/transit) long-distance exchange, TE – transit exchange, ITN – incoming traffic nodes [TE(I) – transit exchange used as ITN], OTN – outgoing traffic nodes [TE(O) – transit exchange used as OTN], OITN – outgoing and incoming traffic node (equivalent to TE), CO – central office, PBX – private branch exchange, C – concentrator, CE – central exchange, LE – local exchange, SN – service node, SL – subscriber line, TL – trunk lines, TS – telephone set.