... voltage:44V~60V BOZZ KTH 18 intrinsically safe automatic telephoneSpecificationsintrinsic safety telephone, with explosion-proof and safety ... ,suitable to coal mine undergroundIntroductionKTH 18 intrinsically safe automatic telephone made by modern electronic technology ,all integrated ... and the protection degree IP54;3) Installation ,desk-top ,hanging type optional, by adopting the newest electronic ...