Does 'telecommunications' refer to only some kinds of networks in modern usage? I know that literally it means 'distance (tele-) communication', but does it refer only to TV or cell phones or internet or something else when used among network engineers?(Do network engineers even use that word to describe what they do?)
As I understand it the term "telecom" (a shortened version of "telecommunications") is usually used to refer to the phone network, the companies that ran it and the technologies that grew out of it. Building computer networks was/is a separate specialism.
What is interesting is in recent years there has been an inversion. It used to be that computer networks were built on top of services provided by the phone network. Nowadays phones are being run over systems designed for computer networking.