Actually the line is 48-52 VDC. Ringing is 20 Hz AC at 90 volts. The ringing will give ya a buzz!!
Correct. (Well, almost correct.)

And I was going to mention the same thing.
It's not AC, it's pulsating DC.
Something I once found out the hard way screwing around with some old telephone test equipment.
It was on the shelf, covered in dust.... and had a rotary dial.
So..... of course, I had to dial "Zero".
I hadn't noticed I was in contact with one of the wires, and didn't realize its internal 45-volt batteries were still kicking.
(Yes, there is something called a 45-volt battery, and it looks like a long 9-volt battery on steroids).
Anyway, "ZAP". (And a pretty decent zap too, even at "low current".)
I try to make a point now to not let curiosity get the better of me.