They are just never assigned. I thought they were specifically set aside to be used in fiction, but it seems like that might have just been 555-01XX. But because of the association to that, no one ever wanted a 555 number for anything else and now they are all unused except for 1 number that leads to ‘directory assistance’
They are just never assigned. I thought they were specifically set aside to be used in fiction, but it seems like that might have just been 555-01XX. But because of the association to that, no one ever wanted a 555 number for anything else and now they are all unused except for 1 number that leads to ‘directory assistance’
https://en.wikipedia.org/wiki/555_(telephone_number)