A Dual SIM Passive phone can use two different SIM cards, but only one of them can be active at any time. That means that when one SIM card works, the other is unreachable. To use the second SIM card, you need to activate it manually, and the first SIM deactivates when you do that.
When you call a dead phone does it ring?
Answer: A: With a dead battery it should not ring but it should go to voicemail directly.