Technical data Explosion-proof marks: Exdib Ⅱ BT5 Gb (Exib Ⅱ CT6 Gb) • rated working voltage: D.C.48V • ringing voltage: A.C.70V, 25Hz • rated working current: 15mA • ringing sound level: > 80dB • call distance: > 5Km(0.5mm2 copper core) • cable outer diameter Product features • this product is designed and manufactured in strict accordance with the requirements of GB3836.1, GB3836.4 and GB15279; • the communication function and use method of this product are completely consistent with ordinary telephone; • this product is designed and manufactured on brand telephone with excellent performance and quality; • clear speech, concise appearance and easy installation and use; • the coupler will fail to meet the electrical signals required by the design of the current and pressure limit, and other measures will be taken to make the output end output in line with the technical requirements of the current and voltage limit.