In response to the comment below: "Confused in my 25 years in Telecom TDM has always and probably will continue to be defined as Time-division Multiplexing."
You are correct. TDM is time division multiplexing. It is the legacy synchronous method of data transport. Even analog telephone calls are encoded as digital information at the first digital switch, and are transmitted over TDM transport systems to their destination.
My point was that legacy synchronous transport systems are being replaced by asynchronous switched packet-switched transport systems. This is the new network schema that techs have to train themselves for if they want to understand how networks operate. This is happening now, not in the distant future.
Field Techs will have to fully understand packet switched technology in the near future when the premise equipment they work on will digitize voice and data traffic right at the customer premise. Would you like an example of how this has been working for many years now? Your cell phone is a end user device that encodes your voice into a digital signal for transport to a distant destination via packet switching and packet switched transport systems. It's digital all the way, end to end, and it always has been from the inception of cell phones. That's what copper techs have to catch up with if they want to stay employed in the near future when copper is completely obsolete everywhere except the extreme rural areas.
If you read my post below carefully, you will see old and new methods, and you will also see different network layers, which are the switching, transport, and local distribution layers. PSN will traverse all of these layers from end user device to end user device, just like cell phones do now, and that is why field techs need to take the initiative to train themselves. They need to stop living dependent on overtime to but that new bass boat motor, and spend a couple of hours on the couch each night training for certifications and/or online degrees in modern telecom networking.
If copper field techs don't know what the OSI model is, they need to learn it top to bottom and understand what telecom industry data is associated to each layer of it. You can't set up test equipment and isolate problems on a packet switched network if you don't know what packet switching is. CTL is going to employ techs who already know what it is, and that's just the way the industry works now, like it or not. That's reality even for me, a career-long union member.