Source docs: Release: https://docs.fcc.gov/public/attachments/DOC-354933A1.pdf https://docs.fcc.gov/public/attachments/DOC-354933A1.pdf Letters: https://www.f

Source docs: Release: https://docs.fcc.gov/public/attachments/DOC-354933A1.pdf https://docs.fcc.gov/public/attachments/DOC-354933A1.pdf Letters: https://www.fcc.gov/document/chairman-pai-demands-industry-adopt-protocols-end-illegal-spoofing https://www.fcc.gov/document/chairman-pai-demands-industry-a... Background on STIR and SHAKEN, which is basically signed caller ID: https://news.ycombinator.com/item?id=17408406 https://news.ycombinator.com/item?id=17408406