Part 23. PART 23—TELEPHONES AND SIGNALING DEVICES
- § 23.1 - Purpose.
- § 23.2 - Definitions.
- § 23.3 - Application procedures and requirements.
- § 23.4 - [Reserved]
- § 23.5 - Conditions governing investigations.
- § 23.6 - General requirements for approval.
- § 23.7 - Specific requirements for approval.
- § 23.8 - Inspection and tests.
- § 23.9 - Special requirements for complete devices.
- § 23.10 - Material required for MSHA records.
- § 23.11 - How approvals are granted.
- § 23.12 - Wording, purpose, and use of approval plate.
- § 23.13 - Withdrawal of approval.
- § 23.14 - Instructions for handling future changes in design.