said by swhx7 
:Consumers are giving up landlines, but telcos are still selling them to businesses. A business or other organization will have its own pbx or whatever in the building, but then it goes to a line in the street.
And as someome else pointed out, once the wireless calls come from the tower they go into copper or fiber.
If a business is tying POTS lines into a PBX they need to leave the 1970's. Multiple lines pulled into a PBX are done via digital circuit (like a T-1, or fractional variant) rather than traditional analog POTS lines.
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