2024 CFR > Title 47 > Chapter I > Subchapter A > Part 9 > Subpart F – Multi-Line Telephone Systems

2023 CFR > Title 47 > CHAPTER I > SUBCHAPTER A > PART 9 > Subpart F – Multi-Line Telephone Systems

2022 CFR > Title 47 > Chapter I > Subchapter A > Part 9 > Subpart F – Multi-Line Telephone Systems

2021 CFR > Title 47 > Chapter I > Subchapter A > Part 9 > Subpart F – Multi-Line Telephone Systems

2020 CFR > Title 47 > Chapter I > Subchapter A > Part 9 > Subpart F – Multi-Line Telephone Systems