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HOME » QUESTION » What’s the reason that i can’t interconnect the HM-638PHM-AC when i cut off the AC power supply and use battery only?

Q：What’s the reason that i can’t interconnect the HM-638PHM-AC when i cut off the AC power supply and use battery only?

A：

The interconnect function act needs the “L””N””I”port all connected by wire.You should connect the 3 interface even though there is no AC power.