KTH107 Coal mine intrinsic safety automatic telephoneDetailed product description：

1. DC open circuit voltage 52V, short-circuit current ≤ 35mA
2. Ring current open circuit voltage 56V (25HZ) short circuit current ≤ 38mA
3. Call frequency 300-3400Hz
4. Ringing sound level ≥ 85dB

The KTH107 coal mine's intrinsic safety automatic telephone and telephone safety coupler are combined with various types of switches and dispatch machines on the ground to form an intrinsic safety explosion-proof communication system.