PART 23--TELEPHONES AND SIGNALING DEVICES
Section
23.1 Purpose.
23.2 Definitions.
23.3 Applications.
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.
Authority: 30 U.S.C. 957 , 961 .
§ 23.2 (f) also issued under 30 U.S.C. 811.
Source: Schedule 9B, 4 FR 1555, Apr. 11, 1939, unless otherwise noted.