can I use nrf51822 realize answer and reject the call? just like HFP?

[gootoomoon]

I just want to handle phone simple call event from iphone4s.

How can I do? Is there any other way to do this?

There are so many media key in hid profile, is there any key for this function?

[David Edwin]

I suggest the you look at the Apple Notification Center Service a.k.a. ANCS, Unfortunately there does not appear to be any call control ability, but you need to get into the details to see what is possible.

The CategoryIDIncomingCall is supported as a category.