> Bluecross will be using POTS modems until the end of time.
 
ROTFL!  Hey, at least they're not using POTTS (= plain old telephone and telegraph system).
 
> I have had customers who still use DOS(!!) programs to .....
 
Me too, before I and those customers parted ways.
 
> (It's kind of like POTS interac terminals, they are still all over the place.)
 
Yes, I still run into those with considerable frequency too!  And they're either tying up a whole dedicated (and expensive) POTS line, or sharing a POTS voice line.
 
> That said, I kind of like POTS modems!  Ah, the good ol' days.
 
Yeah, they make that sound of pterodactyls while they're interchanging carriers and protocols before the real communications session.