... -4 explosion-proof amplifying communication system using ZL102 aluminum alloy die-casting molding, with high-pressure electrostatic plastic-sprayed surface.Phone panel is ... system provides up to 128 word set net, and the distribution of 2 yards, 3 yards and 4 yards of the ... -2, IEC60079-11, EN50014, EN50018, EN50020/392: Exdib II BT6, explosion proof mark is equivalent to the II 2G Exdib II BT6 ...