The phone is intrinsically safe, with regular phone functions, but also has a fully electronic non-contact sensing, the circuit using special techniques, earthquake bell, power consumption, high level of proof. Phone and associated equipment HOB-1 explosion-proof coupling facilities, and switches to form the proof communication system. 

 ● explosive air mixture: IIA, IIB, IIC 
 ● Temperature class: T1-T6 
 ● Indoor and outdoor