Yuantong DM-900 is a DMR digital explosion-proof interphone with Ex ib IIC T4 explosion-proof grade IP67 anti-shower and dust-proof grade/32 communication channels. It supports: one call, group call, full call and digital encryption, which is sufficient to meet most of the needs of high-risk industries such as petrochemical industry. At the same time, the DM-900 also has IP67 high protection capability, which can ensure users to carry out operations calmly in various complex scenes full of water mist and sand, such as fire fighting, oil exploitation, outdoor exploration, etc.