connection request to a known address

Question

Hi guys,
I want to ask if it is possible for a nrf51822 to connect to a Central ( my cell phone) without advertising. Let assume that my cell phone has nrf51822's MAC address from the first connection and it can send a connection request to nrf51822.

RK · Accepted Answer

No it's not. The Bluetooth protocol requires that a device be advertising before it's connectable. You can advertise yourself as connectable to only one central, but you need to advertise.