Legacy Technology: Channelized TDM Transmission Systems
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From about 1960 to 2000, the telecom network was constructed of high-capacity transmission systems shared amongst users by employing Channelized Time-Division Multiplexing (TDM), also known as Synchronous Time-Division Multiplexing.
These systems are now referred to as legacy systems, meaning left over from a previous era... but that does not mean they have disappeared. Telephone companies tend to keep existing systems running for as long as possible.
In this module, you'll learn the channelized DS0-DS1-DS3 digital hierarchy, and technologies like T1 and SONET that implement it.
We'll review how traffic from many different circuits is organized to be communicated together 8,000 times per second in transmission frames.
The module is completed with an overview of the now-almost-completely-obsolete ISDN services.
Telecom Module 17
Detailed Outline
17 Legacy Technology: Channelized TDM Transmission Systems
17.1 The Digital Hierarchy: Legacy Channelized Transmission Speeds
...... 17.1.1 Kilo, Mega, Giga, Tera
...... 17.1.2 DS0
...... 17.1.3 DS1 and E1
...... 17.1.4 DS2
...... 17.1.5 DS3
...... 17.1.6 STM and SDH
17.2 Digital Carrier Systems: Legacy Transmission Technologies
...... 17.2.1 Technologies
...... 17.2.2 Carrier Systems
...... 17.2.3 T1
...... 17.2.4 T3 and Bit-Interleaved Multiplexing
...... 17.2.5 SONET and Byte-Interleaved Multiplexing
...... 17.2.6 SDH
...... 17.2.7 Line Speed vs. Technology
17.3 Framing
...... 17.3.1 Synchronous Time-Division Multiplexing
...... 17.3.2 Framing and Transmission Frames
...... 17.3.3 DS1 Frame
...... 17.3.4 STS-1 (DS3) Frames
...... 17.3.5 SONET Optical Carrier Frames
...... 17.3.6 Advantages and Disadvantages of Channels
17.4 ISDN
...... 17.4.1 Basic Rate Interface (BRI)
...... 17.4.2 Obsolescence of BRI
...... 17.4.3 Primary Rate Interface (PRI)
...... 17.4.4 PRI Physical Connection
...... 17.4.5 T1 vs. PRI
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Eric Coll is an international expert in telecommunications, broadband and networking, and has been actively involved in the telecom industry since 1983. He holds Bachelor of Engineering and Master of Engineering (Electrical) degrees.
Mr. Coll has broad experience, and broad knowledge of telecom developed working as an engineer in the telecommunications industry. Â
He has used his knowledge of telecom to develop and teach telecommunications technology training seminars to wide acclaim across North America since 1992... and answering questions at seminars for companies and organizations ranging from Bell Labs to the Department of Justice keeps things up to date.Â
In his spare time, Mr. Coll authors textbooks and online courses based on the latest updates to the seminar courses.Â
Mr. Coll also provides consulting services as a Subject Matter Expert in telecommunications to government, carriers, and their customers.
