Phone box snap, crackle, pop

Hi All,
One of the phone lines in my house has the snap, crackle, pops.
question: what is the black thing all the wires are attached to? Lightning suppressors?
https://ibb.co/Db4DwMv
Frontier came out and lifted the lines from my house and the noise vanished. So, not the phone company's doing.
Then frontier swapped the two lines and the noise switched from one line to the other line in my house. This before I reversed anything inside the house to accommodate the reversed phone numbers.
He swapped by crossing the gray cables I have circled in red.
https://ibb.co/1Z3QBrG
Seems to me that the problem is not in my house wiring but something between the black thing that the outside lines attached to and where he crossed the two phone lines.
Your take?
Many thanks, -T
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On 3/26/19 9:54 PM, T wrote:

A quick test is to unplug the grey plug/jack wires, and plug in a standard telephone. Whichever line/jack shows the noise, then it is the telco's problem. Somewhere between the demarc jack and their serving Central Office.
That's what those jacks are for.
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