MT 402-1995 Mine production scheduling phone safety coupler general technical specification

GB/T 191-2000 Packaging—Pictorial marking for handling of goods GB/T 191-2008 Packaging—Pictorial marking for handling of goods GB 3836.1-2000 Electrical apparatus for explosive gas atmospheres—Part 1:General requirements GB 3836.1-2010 Explosive atmospheres—Part 1:Equipment—General requirements GB/T 3836.1-2021 Explosive atmospheres—Part 1:Equipment—General requirements GB 3836.4-2000 Electrical apparatus for explosive gas atmospheres—Part 4:Intrinsic safety“i” GB 3836.4-2010 Explosive atmospheres—Part 4:Equipment protection by intrinsic safety "i" GB/T 3836.4-2021 Explosive atmospheres—art 4:Equipment protection by intrinsic safety “i” GB/T 3873-1983 General specifications for products packaging of communication equipments MT 209-1990 The general technical requirements for electrical products used in coal mine communication, detection, and control MT 210-1990 The basic test methods for electrical products used in coal mine communication, detection, and control MT 286-1992 The method for preparing model numbers and management methods for coal mine communication and automation products MT 403-1995 Mining production dispatch manual telephone exchange general technical specifications for telephone switchboard GB/T 191-2025 Graphical symbols marking for handling and storage of packages