I was expecting something about modems. ATDT (555)-COOL-BBS (Totally decentralised btw)
the nanpa is not decentralized at all, though it does delegate phone number assignment to local telecom companies, and nowadays even to sip providers but yeah it seems pretty suboptimal that they decided to reuse the name of the protocol you use to talk to most cellular modems
[1] https://www.iana.org/assignments/uri-schemes/expert-notes/at...