Arthur,
As I said, you are mistaken when you state:
By the way, there is no "RJ12" cord. In fact there is no RJ-anything cord.
I also have spent my career in the informations services area of the telecom sector. I learned early on that there are textbook definitions and there are everyday, working definitons of things, as well.
I always found it was important to be able to communicate effectively by using, in effect, the "vernacular" language lot the persons with whom I was communicating..
Your point of view is along the lines of Rich Melvin's when he sees someone refer to an MU as a "lashup". His thinking comes across as "there's no such thing as a lashup", regardless of the fact that MTH, Lionel and others regularly use this term in product literature.
You're entitled to your opinion, however, please be so kind as to not disallow my use of a common term that is well-understood by those who haven't made their living as members of your industry.
There is, indeed, something called an RJ cable, as well as an RJ jack, because that's what describes those cables for sale to regular people, as this link should serve to illustrate.
Regardless, whether or not I use vernacular, common, everyday language to describe telecom cables, I think that there's little danger of my posts encouraging anyone to connect their AIU to a central office switch.
I'll close with a quote from the Wikipedia link furnished above by VinceL:
...but the term is often used loosely to refer to modular connectors regardless of wiring or gender, such as in Ethernet over twisted pair. There is much confusion over these connection standards. The same six-position plug and jack commonly used for telephone line connections may be used for RJ11, RJ14 or even RJ25, all of which are names of interface standards that use this physical connector. The RJ11 standard dictates a 2-wire connection, while RJ14 uses a 4-wire configuration, and RJ25 uses all six wires. The RJ abbreviations, though, only pertain to the wiring of the jack (hence the name registered jack); it is commonplace but not strictly correct to refer to an unwired plug connector by any of these names.
