KTH18 intrinsically safe automatic telephone with a modern electronic technology, fully integrated circuit is a high performance, high reliability communication terminal. Supporting the KTA17 safety coupler, and the various existing ground switch or scheduling switchboard connected with the composition of the coal mine production scheduling communication system. Automatic telephone safety of KTH18 essence, not only can be used in coal mine, but also can be used in other high-temperature, high humidity, the heavy pollution poor working environment. The main features of the KTH18 intrinsically safe automatic telephone a call from the gain adjustment switch to adjust the gain of the transmission and reception, then, according to the distance of the phone and scheduling switchboard, long distance calls for a coal mine, bad wiring insulation phone The shell is made of anti-static material, waterproof, dustproof, anti-corrosion protection grade IP65, suitable for extremely harsh environments. 3. The keyboard is fully sealed with a luminous touch of a button, the ringing current call sound and light show, and an emergency call, hang up and redial button 4. Wall mount, the switch hook institutions using a newly developed, phone no movable parts.