If neither device A & B are in a call, Ear (2) will play call audio from the device that first receives an incoming call.
If device A has a call in progress, and you receive an incoming call on device B, Ear (2) will play the ringtone at the same time.
If device A hangs up, Ear (2) will switch the call audio to device B.
If you have any further questions about Dual Connection, please check the description on nothing.tech, or contact Nothing Customer Service.